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Man Pages


Manual Reference Pages  -  ZSHALL (1)

NAME

zshall - the Z shell meta-man page

CONTENTS

OVERVIEW

Because zsh contains many features, the zsh manual has been split into a number of sections. This manual page includes all the separate manual pages in the following order:

zshroadmap Informal introduction to the manual
zshmisc Anything not fitting into the other sections
zshexpn Zsh command and parameter expansion
zshparam Zsh parameters
zshoptions Zsh options
zshbuiltins Zsh built-in functions
zshzle Zsh command line editing
zshcompwid Zsh completion widgets
zshcompsys Zsh completion system
zshcompctl Zsh completion control
zshmodules Zsh loadable modules
zshcalsys Zsh built-in calendar functions
zshtcpsys Zsh built-in TCP functions
zshzftpsys Zsh built-in FTP client
zshcontrib Additional zsh functions and utilities
 

DESCRIPTION

Zsh is a UNIX command interpreter (shell) usable as an interactive login shell and as a shell script command processor. Of the standard shells, zsh most closely resembles ksh but includes many enhancements. Zsh has command line editing, builtin spelling correction, programmable command completion, shell functions (with autoloading), a history mechanism, and a host of other features.

AUTHOR

Zsh was originally written by Paul Falstad <pf@zsh.org>. Zsh is now maintained by the members of the zsh-workers mailing list <zsh-workers@zsh.org>. The development is currently coordinated by Peter Stephenson <pws@zsh.org>. The coordinator can be contacted at <coordinator@zsh.org>, but matters relating to the code should generally go to the mailing list.

AVAILABILITY

Zsh is available from the following anonymous FTP sites. These mirror sites are kept frequently up to date. The sites marked with (H) may be mirroring ftp.cs.elte.hu instead of the primary site.

Primary site
 
ftp://ftp.zsh.org/pub/
http://www.zsh.org/pub/

Australia
 
ftp://ftp.zsh.org/pub/
http://www.zsh.org/pub/
http://mirror.dejanseo.com.au/pub/zsh/

Hungary
 
ftp://ftp.cs.elte.hu/pub/zsh/
http://www.cs.elte.hu/pub/zsh/

The up-to-date source code is available via Git from Sourceforge. See http://sourceforge.net/projects/zsh/ for details. A summary of instructions for the archive can be found at http://zsh.sourceforge.net/.

MAILING LISTS

Zsh has 3 mailing lists:

<zsh-announce@zsh.org>
  Announcements about releases, major changes in the shell and the monthly posting of the Zsh FAQ. (moderated)
<zsh-users@zsh.org>
  User discussions.
<zsh-workers@zsh.org>
  Hacking, development, bug reports and patches.
To subscribe or unsubscribe, send mail to the associated administrative address for the mailing list.
<zsh-announce-subscribe@zsh.org>
<zsh-users-subscribe@zsh.org>
<zsh-workers-subscribe@zsh.org>
 
<zsh-announce-unsubscribe@zsh.org>
<zsh-users-unsubscribe@zsh.org>
<zsh-workers-unsubscribe@zsh.org>
 
YOU ONLY NEED TO JOIN ONE OF THE MAILING LISTS AS THEY ARE NESTED. All submissions to zsh-announce are automatically forwarded to zsh-users. All submissions to zsh-users are automatically forwarded to zsh-workers.

If you have problems subscribing/unsubscribing to any of the mailing lists, send mail to <listmaster@zsh.org>. The mailing lists are maintained by Karsten Thygesen <karthy@kom.auc.dk>.

The mailing lists are archived; the archives can be accessed via the administrative addresses listed above. There is also a hypertext archive, maintained by Geoff Wing <gcw@zsh.org>, available at http://www.zsh.org/mla/.

THE ZSH FAQ

Zsh has a list of Frequently Asked Questions (FAQ), maintained by Peter Stephenson <pws@zsh.org>. It is regularly posted to the newsgroup comp.unix.shell and the zsh-announce mailing list. The latest version can be found at any of the Zsh FTP sites, or at http://www.zsh.org/FAQ/. The contact address for FAQ-related matters is <faqmaster@zsh.org>.

THE ZSH WEB PAGE

Zsh has a web page which is located at http://www.zsh.org/. This is maintained by Karsten Thygesen <karthy@zsh.org>, of SunSITE Denmark. The contact address for web-related matters is <webmaster@zsh.org>.

THE ZSH USERGUIDE

A userguide is currently in preparation. It is intended to complement the manual, with explanations and hints on issues where the manual can be cabbalistic, hierographic, or downright mystifying (for example, the word ‘hierographic’ does not exist). It can be viewed in its current state at http://zsh.sourceforge.net/Guide/. At the time of writing, chapters dealing with startup files and their contents and the new completion system were essentially complete.

THE ZSH WIKI

A ‘wiki’ website for zsh has been created at http://www.zshwiki.org/. This is a site which can be added to and modified directly by users without any special permission. You can add your own zsh tips and configurations.

INVOCATION

The following flags are interpreted by the shell when invoked to determine where the shell will read commands from:

-c Take the first argument as a command to execute, rather than reading commands from a script or standard input. If any further arguments are given, the first one is assigned to $0, rather than being used as a positional parameter.
-i Force shell to be interactive. It is still possible to specify a script to execute.
-s Force shell to read commands from the standard input. If the -s flag is not present and an argument is given, the first argument is taken to be the pathname of a script to execute.
If there are any remaining arguments after option processing, and neither of the options -c or -s was supplied, the first argument is taken as the file name of a script containing shell commands to be executed. If the option PATH_SCRIPT is set, and the file name does not contain a directory path (i.e. there is no ‘/’ in the name), first the current directory and then the command path given by the variable PATH are searched for the script. If the option is not set or the file name contains a ‘/’ it is used directly.
After the first one or two arguments have been appropriated as described above, the remaining arguments are assigned to the positional parameters.
For further options, which are common to invocation and the set builtin, see zshoptions(1).
Options may be specified by name using the -o option. -o acts like a single-letter option, but takes a following string as the option name. For example,

 
zsh -x -o shwordsplit scr

runs the script scr, setting the XTRACE option by the corresponding letter ‘-x’ and the SH_WORD_SPLIT option by name. Options may be turned off by name by using +o instead of -o. -o can be stacked up with preceding single-letter options, so for example ‘-xo shwordsplit’ or ‘-xoshwordsplit’ is equivalent to ‘-x -o shwordsplit’.

Options may also be specified by name in GNU long option style, ‘--option-name’. When this is done, ‘-’ characters in the option name are permitted: they are translated into ‘_’, and thus ignored. So, for example, ‘zsh --sh-word-split’ invokes zsh with the SH_WORD_SPLIT option turned on. Like other option syntaxes, options can be turned off by replacing the initial ‘-’ with a ‘+’; thus ‘+-sh-word-split’ is equivalent to ‘--no-sh-word-split’. Unlike other option syntaxes, GNU-style long options cannot be stacked with any other options, so for example ‘-x-shwordsplit’ is an error, rather than being treated like ‘-x --shwordsplit’.

The special GNU-style option ‘--version’ is handled; it sends to standard output the shell’s version information, then exits successfully. ‘--help’ is also handled; it sends to standard output a list of options that can be used when invoking the shell, then exits successfully.

Option processing may be finished, allowing following arguments that start with ‘-’ or ‘+’ to be treated as normal arguments, in two ways. Firstly, a lone ‘-’ (or ‘+’) as an argument by itself ends option processing. Secondly, a special option ‘--’ (or ‘+-’), which may be specified on its own (which is the standard POSIX usage) or may be stacked with preceding options (so ‘-x-’ is equivalent to ‘-x --’). Options are not permitted to be stacked after ‘--’ (so ‘-x-f’ is an error), but note the GNU-style option form discussed above, where ‘--shwordsplit’ is permitted and does not end option processing.

Except when the sh/ksh emulation single-letter options are in effect, the option ‘-b’ (or ‘+b’) ends option processing. ‘-b’ is like ‘--’, except that further single-letter options can be stacked after the ‘-b’ and will take effect as normal.

COMPATIBILITY

Zsh tries to emulate sh or ksh when it is invoked as sh or ksh respectively; more precisely, it looks at the first letter of the name by which it was invoked, excluding any initial ‘r’ (assumed to stand for ‘restricted’), and if that is ‘b’, ‘s’ or ‘k’ it will emulate sh or ksh. Furthermore, if invoked as su (which happens on certain systems when the shell is executed by the su command), the shell will try to find an alternative name from the SHELL environment variable and perform emulation based on that.

In sh and ksh compatibility modes the following parameters are not special and not initialized by the shell: ARGC, argv, cdpath, fignore, fpath, HISTCHARS, mailpath, MANPATH, manpath, path, prompt, PROMPT, PROMPT2, PROMPT3, PROMPT4, psvar, status, watch.

The usual zsh startup/shutdown scripts are not executed. Login shells source /etc/profile followed by $HOME/.profile. If the ENV environment variable is set on invocation, $ENV is sourced after the profile scripts. The value of ENV is subjected to parameter expansion, command substitution, and arithmetic expansion before being interpreted as a pathname. Note that the PRIVILEGED option also affects the execution of startup files.

The following options are set if the shell is invoked as sh or ksh: NO_BAD_PATTERN, NO_BANG_HIST, NO_BG_NICE, NO_EQUALS, NO_FUNCTION_ARGZERO, GLOB_SUBST, NO_GLOBAL_EXPORT, NO_HUP, INTERACTIVE_COMMENTS, KSH_ARRAYS, NO_MULTIOS, NO_NOMATCH, NO_NOTIFY, POSIX_BUILTINS, NO_PROMPT_PERCENT, RM_STAR_SILENT, SH_FILE_EXPANSION, SH_GLOB, SH_OPTION_LETTERS, SH_WORD_SPLIT. Additionally the BSD_ECHO and IGNORE_BRACES options are set if zsh is invoked as sh. Also, the KSH_OPTION_PRINT, LOCAL_OPTIONS, PROMPT_BANG, PROMPT_SUBST and SINGLE_LINE_ZLE options are set if zsh is invoked as ksh.

RESTRICTED SHELL

When the basename of the command used to invoke zsh starts with the letter ‘r’ or the ‘-r’ command line option is supplied at invocation, the shell becomes restricted. Emulation mode is determined after stripping the letter ‘r’ from the invocation name. The following are disabled in restricted mode:

o changing directories with the cd builtin
o changing or unsetting the PATH, path, MODULE_PATH, module_path, SHELL, HISTFILE, HISTSIZE, GID, EGID, UID, EUID, USERNAME, LD_LIBRARY_PATH, LD_AOUT_LIBRARY_PATH, LD_PRELOAD and LD_AOUT_PRELOAD parameters
o specifying command names containing /
o specifying command pathnames using hash
o redirecting output to files
o using the exec builtin command to replace the shell with another command
o using jobs -Z to overwrite the shell process’ argument and environment space
o using the ARGV0 parameter to override argv[0] for external commands
o turning off restricted mode with set +r or unsetopt RESTRICTED
These restrictions are enforced after processing the startup files. The startup files should set up PATH to point to a directory of commands which can be safely invoked in the restricted environment. They may also add further restrictions by disabling selected builtins.

Restricted mode can also be activated any time by setting the RESTRICTED option. This immediately enables all the restrictions described above even if the shell still has not processed all startup files.

STARTUP/SHUTDOWN FILES

Commands are first read from /etc/zshenv; this cannot be overridden. Subsequent behaviour is modified by the RCS and GLOBAL_RCS options; the former affects all startup files, while the second only affects global startup files (those shown here with an path starting with a /). If one of the options is unset at any point, any subsequent startup file(s) of the corresponding type will not be read. It is also possible for a file in $ZDOTDIR to re-enable GLOBAL_RCS. Both RCS and GLOBAL_RCS are set by default.

Commands are then read from $ZDOTDIR/.zshenv. If the shell is a login shell, commands are read from /etc/zprofile and then $ZDOTDIR/.zprofile. Then, if the shell is interactive, commands are read from /etc/zshrc and then $ZDOTDIR/.zshrc. Finally, if the shell is a login shell, /etc/zlogin and $ZDOTDIR/.zlogin are read.

When a login shell exits, the files $ZDOTDIR/.zlogout and then /etc/zlogout are read. This happens with either an explicit exit via the exit or logout commands, or an implicit exit by reading end-of-file from the terminal. However, if the shell terminates due to exec’ing another process, the logout files are not read. These are also affected by the RCS and GLOBAL_RCS options. Note also that the RCS option affects the saving of history files, i.e. if RCS is unset when the shell exits, no history file will be saved.

If ZDOTDIR is unset, HOME is used instead. Files listed above as being in /etc may be in another directory, depending on the installation.

As /etc/zshenv is run for all instances of zsh, it is important that it be kept as small as possible. In particular, it is a good idea to put code that does not need to be run for every single shell behind a test of the form ‘if [[ -o rcs ]]; then ...’ so that it will not be executed when zsh is invoked with the ‘-f’ option.

Any of these files may be pre-compiled with the zcompile builtin command (see zshbuiltins(1)). If a compiled file exists (named for the original file plus the .zwc extension) and it is newer than the original file, the compiled file will be used instead.

NAME

zshroadmap - informal introduction to the zsh manual The Zsh Manual, like the shell itself, is large and often complicated. This section of the manual provides some pointers to areas of the shell that are likely to be of particular interest to new users, and indicates where in the rest of the manual the documentation is to be found.

WHEN THE SHELL STARTS

When it starts, the shell reads commands from various files. These can be created or edited to customize the shell. See the section Startup/Shutdown Files in zsh(1).

If no personal initialization files exist for the current user, a function is run to help you change some of the most common settings. It won’t appear if your administrator has disabled the zsh/newuser module. The function is designed to be self-explanatory. You can run it by hand with ‘autoload -Uz zsh-newuser-install; zsh-newuser-install -f’. See also the section User Configuration Functions in zshcontrib(1).

INTERACTIVE USE

Interaction with the shell uses the builtin Zsh Line Editor, ZLE. This is described in detail in zshzle(1).

The first decision a user must make is whether to use the Emacs or Vi editing mode as the keys for editing are substantially different. Emacs editing mode is probably more natural for beginners and can be selected explicitly with the command bindkey -e.

A history mechanism for retrieving previously typed lines (most simply with the Up or Down arrow keys) is available; note that, unlike other shells, zsh will not save these lines when the shell exits unless you set appropriate variables, and the number of history lines retained by default is quite small (30 lines). See the description of the shell variables (referred to in the documentation as parameters) HISTFILE, HISTSIZE and SAVEHIST in zshparam(1). Note that it’s currently only possible to read and write files saving history when the shell is interactive, i.e. it does not work from scripts.

The shell now supports the UTF-8 character set (and also others if supported by the operating system). This is (mostly) handled transparently by the shell, but the degree of support in terminal emulators is variable. There is some discussion of this in the shell FAQ, http://www.zsh.org/FAQ/. Note in particular that for combining characters to be handled the option COMBINING_CHARS needs to be set. Because the shell is now more sensitive to the definition of the character set, note that if you are upgrading from an older version of the shell you should ensure that the appropriate variable, either LANG (to affect all aspects of the shell’s operation) or LC_CTYPE (to affect only the handling of character sets) is set to an appropriate value. This is true even if you are using a single-byte character set including extensions of ASCII such as ISO-8859-1 or ISO-8859-15. See the description of LC_CTYPE in zshparam(1).

    Completion

Completion is a feature present in many shells. It allows the user to type only a part (usually the prefix) of a word and have the shell fill in the rest. The completion system in zsh is programmable. For example, the shell can be set to complete email addresses in arguments to the mail command from your ~/.abook/addressbook; usernames, hostnames, and even remote paths in arguments to scp, and so on. Anything that can be written in or glued together with zsh can be the source of what the line editor offers as possible completions.

Zsh has two completion systems, an old, so called compctl completion (named after the builtin command that serves as its complete and only user interface), and a new one, referred to as compsys, organized as library of builtin and user-defined functions. The two systems differ in their interface for specifying the completion behavior. The new system is more customizable and is supplied with completions for many commonly used commands; it is therefore to be preferred.

The completion system must be enabled explicitly when the shell starts. For more information see zshcompsys(1).

    Extending the line editor

Apart from completion, the line editor is highly extensible by means of shell functions. Some useful functions are provided with the shell; they provide facilities such as:

insert-composed-char
  composing characters not found on the keyboard
match-words-by-style
  configuring what the line editor considers a word when moving or deleting by word
history-beginning-search-backward-end, etc.
  alternative ways of searching the shell history
replace-string, replace-pattern
  functions for replacing strings or patterns globally in the command line
edit-command-line
  edit the command line with an external editor.
See the section ‘ZLE Functions’ in zshcontrib(1) for descriptions of these.

OPTIONS

The shell has a large number of options for changing its behaviour. These cover all aspects of the shell; browsing the full documentation is the only good way to become acquainted with the many possibilities. See zshoptions(1).

PATTERN MATCHING

The shell has a rich set of patterns which are available for file matching (described in the documentation as ‘filename generation’ and also known for historical reasons as ‘globbing’) and for use when programming. These are described in the section ‘Filename Generation’ in zshexpn(1).

Of particular interest are the following patterns that are not commonly supported by other systems of pattern matching:

** for matching over multiple directories
~, ^ the ability to exclude patterns from matching when the EXTENDED_GLOB option is set
(...) glob qualifiers, included in parentheses at the end of the pattern, which select files by type (such as directories) or attribute (such as size).

GENERAL COMMENTS ON SYNTAX

Although the syntax of zsh is in ways similar to the Korn shell, and therefore more remotely to the original UNIX shell, the Bourne shell, its default behaviour does not entirely correspond to those shells. General shell syntax is introduced in the section ‘Shell Grammar’ in zshmisc(1).

One commonly encountered difference is that variables substituted onto the command line are not split into words. See the description of the shell option SH_WORD_SPLIT in the section ‘Parameter Expansion’ in zshexpn(1). In zsh, you can either explicitly request the splitting (e.g. ${=foo}) or use an array when you want a variable to expand to more than one word. See the section ‘Array Parameters’ in zshparam(1).

PROGRAMMING

The most convenient way of adding enhancements to the shell is typically by writing a shell function and arranging for it to be autoloaded. Functions are described in the section ‘Functions’ in zshmisc(1). Users changing from the C shell and its relatives should notice that aliases are less used in zsh as they don’t perform argument substitution, only simple text replacement.

A few general functions, other than those for the line editor described above, are provided with the shell and are described in zshcontrib(1). Features include:

promptinit
  a prompt theme system for changing prompts easily, see the section ‘Prompt Themes’

zsh-mime-setup
  a MIME-handling system which dispatches commands according to the suffix of a file as done by graphical file managers
zcalc a calculator
zargs a version of xargs that makes the find command redundant
zmv a command for renaming files by means of shell patterns.

NAME

zshmisc - everything and then some

SIMPLE COMMANDS & PIPELINES

A simple command is a sequence of optional parameter assignments followed by blank-separated words, with optional redirections interspersed. For a description of assignment, see the beginning of zshparam(1).

The first word is the command to be executed, and the remaining words, if any, are arguments to the command. If a command name is given, the parameter assignments modify the environment of the command when it is executed. The value of a simple command is its exit status, or 128 plus the signal number if terminated by a signal. For example,

echo foo

is a simple command with arguments.

A pipeline is either a simple command, or a sequence of two or more simple commands where each command is separated from the next by ‘|’ or ‘|&’. Where commands are separated by ‘|’, the standard output of the first command is connected to the standard input of the next. ‘|&’ is shorthand for ‘2>&1 |’, which connects both the standard output and the standard error of the command to the standard input of the next. The value of a pipeline is the value of the last command, unless the pipeline is preceded by ‘!’ in which case the value is the logical inverse of the value of the last command. For example,

echo foo | sed ’s/foo/bar/’

is a pipeline, where the output (‘foo’ plus a newline) of the first command will be passed to the input of the second.

If a pipeline is preceded by ‘coproc’, it is executed as a coprocess; a two-way pipe is established between it and the parent shell. The shell can read from or write to the coprocess by means of the ‘>&p’ and ‘<&p’ redirection operators or with ‘print -p’ and ‘read -p’. A pipeline cannot be preceded by both ‘coproc’ and ‘!’. If job control is active, the coprocess can be treated in other than input and output as an ordinary background job.

A sublist is either a single pipeline, or a sequence of two or more pipelines separated by ‘&&’ or ‘||’. If two pipelines are separated by ‘&&’, the second pipeline is executed only if the first succeeds (returns a zero status). If two pipelines are separated by ‘||’, the second is executed only if the first fails (returns a nonzero status). Both operators have equal precedence and are left associative. The value of the sublist is the value of the last pipeline executed. For example,

dmesg | grep panic && print yes

is a sublist consisting of two pipelines, the second just a simple command which will be executed if and only if the grep command returns a zero status. If it does not, the value of the sublist is that return status, else it is the status returned by the print (almost certainly zero).

A list is a sequence of zero or more sublists, in which each sublist is terminated by ‘;’, ‘&’, ‘&|’, ‘&!’, or a newline. This terminator may optionally be omitted from the last sublist in the list when the list appears as a complex command inside ‘(...)’ or ‘{...}’. When a sublist is terminated by ‘;’ or newline, the shell waits for it to finish before executing the next sublist. If a sublist is terminated by a ‘&’, ‘&|’, or ‘&!’, the shell executes the last pipeline in it in the background, and does not wait for it to finish (note the difference from other shells which execute the whole sublist in the background). A backgrounded pipeline returns a status of zero.

More generally, a list can be seen as a set of any shell commands whatsoever, including the complex commands below; this is implied wherever the word ‘list’ appears in later descriptions. For example, the commands in a shell function form a special sort of list.

PRECOMMAND MODIFIERS

A simple command may be preceded by a precommand modifier, which will alter how the command is interpreted. These modifiers are shell builtin commands with the exception of nocorrect which is a reserved word.

- The command is executed with a ‘-’ prepended to its argv[0] string.
builtin
  The command word is taken to be the name of a builtin command, rather than a shell function or external command.
command [ -pvV ]
  The command word is taken to be the name of an external command, rather than a shell function or builtin. If the POSIX_BUILTINS option is set, builtins will also be executed but certain special properties of them are suppressed. The -p flag causes a default path to be searched instead of that in $path. With the -v flag, command is similar to whence and with -V, it is equivalent to whence -v.
exec [ -cl ] [ -a argv0 ]
  The following command together with any arguments is run in place of the current process, rather than as a sub-process. The shell does not fork and is replaced. The shell does not invoke TRAPEXIT, nor does it source zlogout files. The options are provided for compatibility with other shells.

The -c option clears the environment.

The -l option is equivalent to the - precommand modifier, to treat the replacement command as a login shell; the command is executed with a - prepended to its argv[0] string. This flag has no effect if used together with the -a option.

The -a option is used to specify explicitly the argv[0] string (the name of the command as seen by the process itself) to be used by the replacement command and is directly equivalent to setting a value for the ARGV0 environment variable.

nocorrect
  Spelling correction is not done on any of the words. This must appear before any other precommand modifier, as it is interpreted immediately, before any parsing is done. It has no effect in non-interactive shells.
noglob Filename generation (globbing) is not performed on any of the words.

COMPLEX COMMANDS

A complex command in zsh is one of the following:

if list then list [ elif list then list ] ... [ else list ] fi
  The if list is executed, and if it returns a zero exit status, the then list is executed. Otherwise, the elif list is executed and if its status is zero, the then list is executed. If each elif list returns nonzero status, the else list is executed.
for name ... [ in word ... ] term do list done
  where term is at least one newline or ;. Expand the list of words, and set the parameter name to each of them in turn, executing list each time. If the in word is omitted, use the positional parameters instead of the words.

More than one parameter name can appear before the list of words. If N names are given, then on each execution of the loop the next N words are assigned to the corresponding parameters. If there are more names than remaining words, the remaining parameters are each set to the empty string. Execution of the loop ends when there is no remaining word to assign to the first name. It is only possible for in to appear as the first name in the list, else it will be treated as marking the end of the list.

for (( [expr1] ; [expr2] ; [expr3] )) do list done
  The arithmetic expression expr1 is evaluated first (see the section ‘Arithmetic Evaluation’). The arithmetic expression expr2 is repeatedly evaluated until it evaluates to zero and when non-zero, list is executed and the arithmetic expression expr3 evaluated. If any expression is omitted, then it behaves as if it evaluated to 1.
while list do list done
  Execute the do list as long as the while list returns a zero exit status.
until list do list done
  Execute the do list as long as until list returns a nonzero exit status.
repeat word do list done
  word is expanded and treated as an arithmetic expression, which must evaluate to a number n. list is then executed n times.

The repeat syntax is disabled by default when the shell starts in a mode emulating another shell. It can be enabled with the command ‘enable -r repeat

case word in [ [(] pattern [ | pattern ] ... ) list (;;|;&|;|) ] ... esac
  Execute the list associated with the first pattern that matches word, if any. The form of the patterns is the same as that used for filename generation. See the section ‘Filename Generation’.

Note further that, unless the SH_GLOB option is set, the whole pattern with alternatives is treated by the shell as equivalent to a group of patterns within parentheses, although white space may appear about the parentheses and the vertical bar and will be stripped from the pattern at those points. White space may appear elsewhere in the pattern; this is not stripped. If the SH_GLOB option is set, so that an opening parenthesis can be unambiguously treated as part of the case syntax, the expression is parsed into separate words and these are treated as strict alternatives (as in other shells).

If the list that is executed is terminated with ;& rather than ;;, the following list is also executed. The rule for the terminator of the following list ;;, ;& or ;| is applied unless the esac is reached.

If the list that is executed is terminated with ;| the shell continues to scan the patterns looking for the next match, executing the corresponding list, and applying the rule for the corresponding terminator ;;, ;& or ;|. Note that word is not re-expanded; all applicable patterns are tested with the same word.

select name [ in word ... term ] do list done
  where term is one or more newline or ; to terminate the words. Print the set of words, each preceded by a number. If the in word is omitted, use the positional parameters. The PROMPT3 prompt is printed and a line is read from the line editor if the shell is interactive and that is active, or else standard input. If this line consists of the number of one of the listed words, then the parameter name is set to the word corresponding to this number. If this line is empty, the selection list is printed again. Otherwise, the value of the parameter name is set to null. The contents of the line read from standard input is saved in the parameter REPLY. list is executed for each selection until a break or end-of-file is encountered.
( list ) Execute list in a subshell. Traps set by the trap builtin are reset to their default values while executing list.
{ list }
  Execute list.
{ try-list } always { always-list }
  First execute try-list. Regardless of errors, or break, continue, or return commands encountered within try-list, execute always-list. Execution then continues from the result of the execution of try-list; in other words, any error, or break, continue, or return command is treated in the normal way, as if always-list were not present. The two chunks of code are referred to as the ‘try block’ and the ‘always block’.

Optional newlines or semicolons may appear after the always; note, however, that they may not appear between the preceding closing brace and the always.

An ‘error’ in this context is a condition such as a syntax error which causes the shell to abort execution of the current function, script, or list. Syntax errors encountered while the shell is parsing the code do not cause the always-list to be executed. For example, an erroneously constructed if block in try-list would cause the shell to abort during parsing, so that always-list would not be executed, while an erroneous substitution such as ${*foo*} would cause a run-time error, after which always-list would be executed.

An error condition can be tested and reset with the special integer variable TRY_BLOCK_ERROR. Outside an always-list the value is irrelevant, but it is initialised to -1. Inside always-list, the value is 1 if an error occurred in the try-list, else 0. If TRY_BLOCK_ERROR is set to 0 during the always-list, the error condition caused by the try-list is reset, and shell execution continues normally after the end of always-list. Altering the value during the try-list is not useful (unless this forms part of an enclosing always block).

Regardless of TRY_BLOCK_ERROR, after the end of always-list the normal shell status $? is the value returned from try-list. This will be non-zero if there was an error, even if TRY_BLOCK_ERROR was set to zero.

The following executes the given code, ignoring any errors it causes. This is an alternative to the usual convention of protecting code by executing it in a subshell.

 
{
    # code which may cause an error
  } always {
    # This code is executed regardless of the error.
    (( TRY_BLOCK_ERROR = 0 ))
}
# The error condition has been reset.

An exit command (or a return command executed at the outermost function level of a script) encountered in try-list does not cause the execution of always-list. Instead, the shell exits immediately after any EXIT trap has been executed.

function word ... [ () ] [ term ] { list }
word ... () [ term ] { list }
word ... () [ term ] command
  where term is one or more newline or ;. Define a function which is referenced by any one of word. Normally, only one word is provided; multiple words are usually only useful for setting traps. The body of the function is the list between the { and }. See the section ‘Functions’.

If the option SH_GLOB is set for compatibility with other shells, then whitespace may appear between the left and right parentheses when there is a single word; otherwise, the parentheses will be treated as forming a globbing pattern in that case.

In any of the forms above, a redirection may appear outside the function body, for example

 
func() { ... } 2>&1

The redirection is stored with the function and applied whenever the function is executed. Any variables in the redirection are expanded at the point the function is executed, but outside the function scope.

time [ pipeline ]
  The pipeline is executed, and timing statistics are reported on the standard error in the form specified by the TIMEFMT parameter. If pipeline is omitted, print statistics about the shell process and its children.
[[ exp ]]
  Evaluates the conditional expression exp and return a zero exit status if it is true. See the section ‘Conditional Expressions’ for a description of exp.

ALTERNATE FORMS FOR COMPLEX COMMANDS

Many of zsh’s complex commands have alternate forms. These are non-standard and are likely not to be obvious even to seasoned shell programmers; they should not be used anywhere that portability of shell code is a concern.

The short versions below only work if sublist is of the form ‘{ list }’ or if the SHORT_LOOPS option is set. For the if, while and until commands, in both these cases the test part of the loop must also be suitably delimited, such as by ‘[[ ... ]]’ or ‘(( ... ))’, else the end of the test will not be recognized. For the for, repeat, case and select commands no such special form for the arguments is necessary, but the other condition (the special form of sublist or use of the SHORT_LOOPS option) still applies.

if list { list } [ elif list { list } ] ... [ else { list } ]
  An alternate form of if. The rules mean that

 
if [[ -o ignorebraces ]] {
  print yes
}

works, but

 
if true {  # Does not work!
  print yes
}

does not, since the test is not suitably delimited.

if list sublist
  A short form of the alternate if. The same limitations on the form of list apply as for the previous form.
for name ... ( word ... ) sublist
  A short form of for.
for name ... [ in word ... ] term sublist
  where term is at least one newline or ;. Another short form of for.
for (( [expr1] ; [expr2] ; [expr3] )) sublist
  A short form of the arithmetic for command.
foreach name ... ( word ... ) list end
  Another form of for.
while list { list }
  An alternative form of while. Note the limitations on the form of list mentioned above.
until list { list }
  An alternative form of until. Note the limitations on the form of list mentioned above.
repeat word sublist
  This is a short form of repeat.
case word { [ [(] pattern [ | pattern ] ... ) list (;;|;&|;|) ] ... }
  An alternative form of case.
select name [ in word ... term ] sublist
  where term is at least one newline or ;. A short form of select.

RESERVED WORDS

The following words are recognized as reserved words when used as the first word of a command unless quoted or disabled using disable -r:

do done esac then elif else fi for case if while function repeat time until select coproc nocorrect foreach end ! [[ { } declare export float integer local readonly typeset

Additionally, ‘}’ is recognized in any position if neither the IGNORE_BRACES option nor the IGNORE_CLOSE_BRACES option is set.

ERRORS

Certain errors are treated as fatal by the shell: in an interactive shell, they cause control to return to the command line, and in a non-interactive shell they cause the shell to be aborted. In older versions of zsh, a non-interactive shell running a script would not abort completely, but would resume execution at the next command to be read from the script, skipping the remainder of any functions or shell constructs such as loops or conditions; this somewhat illogical behaviour can be recovered by setting the option CONTINUE_ON_ERROR.

Fatal errors found in non-interactive shells include:

o Failure to parse shell options passed when invoking the shell
o Failure to change options with the set builtin
o Parse errors of all sorts, including failures to parse mathematical expressions
o Failures to set or modify variable behaviour with typeset, local, declare, export, integer, float
o Execution of incorrectly positioned loop control structures (continue, break)
o Attempts to use regular expression with no regular expression module available
o Disallowed operations when the RESTRICTED options is set
o Failure to create a pipe needed for a pipeline
o Failure to create a multio
o Failure to autoload a module needed for a declared shell feature
o Errors creating command or process substitutions
o Syntax errors in glob qualifiers
o File generation errors where not caught by the option BAD_PATTERN
o All bad patterns used for matching within case statements
o File generation failures where not caused by NO_MATCH or similar options
o All file generation errors where the pattern was used to create a multio
o Memory errors where detected by the shell
o Invalid subscripts to shell variables
o Attempts to assign read-only variables
o Logical errors with variables such as assignment to the wrong type
o Use of invalid variable names
o Errors in variable substitution syntax
o Failure to convert characters in $’... expressions
If the POSIX_BUILTINS option is set, more errors associated with shell builtin commands are treated as fatal, as specified by the POSIX standard.

COMMENTS

In non-interactive shells, or in interactive shells with the INTERACTIVE_COMMENTS option set, a word beginning with the third character of the histchars parameter (‘#’ by default) causes that word and all the following characters up to a newline to be ignored.

ALIASING

Every eligible word in the shell input is checked to see if there is an alias defined for it. If so, it is replaced by the text of the alias if it is in command position (if it could be the first word of a simple command), or if the alias is global. If the replacement text ends with a space, the next word in the shell input is always eligible for purposes of alias expansion. An alias is defined using the alias builtin; global aliases may be defined using the -g option to that builtin.

A word is defined as:

o Any plain string or glob pattern
o Any quoted string, using any quoting method (note that the quotes must be part of the alias definition for this to be eligible)
o Any parameter reference or command substitution
o Any series of the foregoing, concatenated without whitespace or other tokens between them
o Any reserved word (case, do, else, etc.)
o With global aliasing, any command separator, any redirection operator, and ‘(’ or ‘)’ when not part of a glob pattern
It is not presently possible to alias the ‘((’ token that introduces arithmetic expressions, because until a full statement has been parsed, it cannot be distinguished from two consecutive ‘(’ tokens introducing nested subshells.
When POSIX_ALIASES is set, only plain unquoted strings are eligible for aliasing. The alias builtin does not reject ineligible aliases, but they are not expanded.
Alias expansion is done on the shell input before any other expansion except history expansion. Therefore, if an alias is defined for the word foo, alias expansion may be avoided by quoting part of the word, e.g. \foo. Any form of quoting works, although there is nothing to prevent an alias being defined for the quoted form such as \foo as well. Also, if a separator such as && is aliased, \&& turns into the two tokens \& and &, each of which may have been aliased separately. Similarly for \<<, \>|, etc.
For use with completion, which would remove an initial backslash followed by a character that isn’t special, it may be more convenient to quote the word by starting with a single quote, i.e. ’foo; completion will automatically add the trailing single quote.
There is a commonly encountered problem with aliases illustrated by the following code:

 
alias echobar=’echo bar’; echobar

This prints a message that the command echobar could not be found. This happens because aliases are expanded when the code is read in; the entire line is read in one go, so that when echobar is executed it is too late to expand the newly defined alias. This is often a problem in shell scripts, functions, and code executed with ‘source’ or ‘.’. Consequently, use of functions rather than aliases is recommended in non-interactive code.
Note also the unhelpful interaction of aliases and function definitions:

 
alias func=’noglob func’
func() {
    echo Do something with $*
}

Because aliases are expanded in function definitions, this causes the following command to be executed:

 
noglob func() {
    echo Do something with $*
}

which defines noglob as well as func as functions with the body given. To avoid this, either quote the name func or use the alternative function definition form ‘function func’. Ensuring the alias is defined after the function works but is problematic if the code fragment might be re-executed.

QUOTING

A character may be quoted (that is, made to stand for itself) by preceding it with a ‘\’. ‘\’ followed by a newline is ignored.

A string enclosed between ‘$’’ and ‘’ is processed the same way as the string arguments of the print builtin, and the resulting string is considered to be entirely quoted. A literal ‘’ character can be included in the string by using the ‘\’’ escape.

All characters enclosed between a pair of single quotes (’’) that is not preceded by a ‘$’ are quoted. A single quote cannot appear within single quotes unless the option RC_QUOTES is set, in which case a pair of single quotes are turned into a single quote. For example,

print ’’’’

outputs nothing apart from a newline if RC_QUOTES is not set, but one single quote if it is set.

Inside double quotes (""), parameter and command substitution occur, and ‘\’ quotes the characters ‘\’, ‘’, ‘"’, and ‘$’.

REDIRECTION

If a command is followed by & and job control is not active, then the default standard input for the command is the empty file /dev/null. Otherwise, the environment for the execution of a command contains the file descriptors of the invoking shell as modified by input/output specifications.

The following may appear anywhere in a simple command or may precede or follow a complex command. Expansion occurs before word or digit is used except as noted below. If the result of substitution on word produces more than one filename, redirection occurs for each separate filename in turn.

< word Open file word for reading as standard input.
<> word
  Open file word for reading and writing as standard input. If the file does not exist then it is created.
> word Open file word for writing as standard output. If the file does not exist then it is created. If the file exists, and the CLOBBER option is unset, this causes an error; otherwise, it is truncated to zero length.
>| word
>! word
Same as >, except that the file is truncated to zero length if it exists, even if CLOBBER is unset.
>> word
  Open file word for writing in append mode as standard output. If the file does not exist, and the CLOBBER option is unset, this causes an error; otherwise, the file is created.
>>| word
>>! word
  Same as >>, except that the file is created if it does not exist, even if CLOBBER is unset.
<<[-] word
  The shell input is read up to a line that is the same as word, or to an end-of-file. No parameter expansion, command substitution or filename generation is performed on word. The resulting document, called a here-document, becomes the standard input.

If any character of word is quoted with single or double quotes or a ‘\’, no interpretation is placed upon the characters of the document. Otherwise, parameter and command substitution occurs, ‘\’ followed by a newline is removed, and ‘\’ must be used to quote the characters ‘\’, ‘$’, ‘’ and the first character of word.

Note that word itself does not undergo shell expansion. Backquotes in word do not have their usual effect; instead they behave similarly to double quotes, except that the backquotes themselves are passed through unchanged. (This information is given for completeness and it is not recommended that backquotes be used.) Quotes in the form $’... have their standard effect of expanding backslashed references to special characters.

If <<- is used, then all leading tabs are stripped from word and from the document.

<<< word
  Perform shell expansion on word and pass the result to standard input. This is known as a here-string. Compare the use of word in here-documents above, where word does not undergo shell expansion.
<& number
>& number
  The standard input/output is duplicated from file descriptor number (see dup2(2)).
<& -
>& -
Close the standard input/output.
<& p
>& p
The input/output from/to the coprocess is moved to the standard input/output.
>& word
&> word
  (Except where ‘>& word’ matches one of the above syntaxes; ‘&>’ can always be used to avoid this ambiguity.) Redirects both standard output and standard error (file descriptor 2) in the manner of ‘> word’. Note that this does not have the same effect as ‘> word 2>&1’ in the presence of multios (see the section below).
>&| word
>&! word
&>| word
&>! word
  Redirects both standard output and standard error (file descriptor 2) in the manner of ‘>| word’.
>>& word
&>> word
  Redirects both standard output and standard error (file descriptor 2) in the manner of ‘>> word’.
>>&| word
>>&! word
&>>| word
&>>! word
  Redirects both standard output and standard error (file descriptor 2) in the manner of ‘>>| word’.
If one of the above is preceded by a digit, then the file descriptor referred to is that specified by the digit instead of the default 0 or 1. The order in which redirections are specified is significant. The shell evaluates each redirection in terms of the (file descriptor, file) association at the time of evaluation. For example:

 
... 1>fname 2>&1

first associates file descriptor 1 with file fname. It then associates file descriptor 2 with the file associated with file descriptor 1 (that is, fname). If the order of redirections were reversed, file descriptor 2 would be associated with the terminal (assuming file descriptor 1 had been) and then file descriptor 1 would be associated with file fname.

The ‘|&’ command separator described in Simple Commands & Pipelines in zshmisc(1) is a shorthand for ‘2>&1 |’.

The various forms of process substitution, ‘<(list)’, and ‘=(list)’ for input and ‘>(list)’ for output, are often used together with redirection. For example, if word in an output redirection is of the form ‘>(list)’ then the output is piped to the command represented by list. See Process Substitution in zshexpn(1).

OPENING FILE DESCRIPTORS USING PARAMETERS

When the shell is parsing arguments to a command, and the shell option IGNORE_BRACES is not set, a different form of redirection is allowed: instead of a digit before the operator there is a valid shell identifier enclosed in braces. The shell will open a new file descriptor that is guaranteed to be at least 10 and set the parameter named by the identifier to the file descriptor opened. No whitespace is allowed between the closing brace and the redirection character. For example:

... {myfd}>&1

This opens a new file descriptor that is a duplicate of file descriptor 1 and sets the parameter myfd to the number of the file descriptor, which will be at least 10. The new file descriptor can be written to using the syntax >&$myfd.

The syntax {varid}>&-, for example {myfd}>&-, may be used to close a file descriptor opened in this fashion. Note that the parameter given by varid must previously be set to a file descriptor in this case.

It is an error to open or close a file descriptor in this fashion when the parameter is readonly. However, it is not an error to read or write a file descriptor using <&$param or >&$param if param is readonly.

If the option CLOBBER is unset, it is an error to open a file descriptor using a parameter that is already set to an open file descriptor previously allocated by this mechanism. Unsetting the parameter before using it for allocating a file descriptor avoids the error.

Note that this mechanism merely allocates or closes a file descriptor; it does not perform any redirections from or to it. It is usually convenient to allocate a file descriptor prior to use as an argument to exec. The syntax does not in any case work when used around complex commands such as parenthesised subshells or loops, where the opening brace is interpreted as part of a command list to be executed in the current shell.

The following shows a typical sequence of allocation, use, and closing of a file descriptor:

integer myfd
exec {myfd}>~/logs/mylogfile.txt
print This is a log message. >&$myfd
exec {myfd}>&-

Note that the expansion of the variable in the expression >&$myfd occurs at the point the redirection is opened. This is after the expansion of command arguments and after any redirections to the left on the command line have been processed.

MULTIOS

If the user tries to open a file descriptor for writing more than once, the shell opens the file descriptor as a pipe to a process that copies its input to all the specified outputs, similar to tee, provided the MULTIOS option is set, as it is by default. Thus:

date >foo >bar

writes the date to two files, named ‘foo’ and ‘bar’. Note that a pipe is an implicit redirection; thus

date >foo | cat

writes the date to the file ‘foo’, and also pipes it to cat.

If the MULTIOS option is set, the word after a redirection operator is also subjected to filename generation (globbing). Thus

: > *

will truncate all files in the current directory, assuming there’s at least one. (Without the MULTIOS option, it would create an empty file called ‘*’.) Similarly, you can do

echo exit 0 >> *.sh

If the user tries to open a file descriptor for reading more than once, the shell opens the file descriptor as a pipe to a process that copies all the specified inputs to its output in the order specified, similar to cat, provided the MULTIOS option is set. Thus

sort <foo <fubar

or even

sort <f{oo,ubar}

is equivalent to ‘cat foo fubar | sort’.

Expansion of the redirection argument occurs at the point the redirection is opened, at the point described above for the expansion of the variable in >&$myfd.

Note that a pipe is an implicit redirection; thus

cat bar | sort <foo

is equivalent to ‘cat bar foo | sort’ (note the order of the inputs).

If the MULTIOS option is unset, each redirection replaces the previous redirection for that file descriptor. However, all files redirected to are actually opened, so

echo Hello > bar > baz

when MULTIOS is unset will truncate ‘bar’, and write ‘Hello’ into ‘baz’.

There is a problem when an output multio is attached to an external program. A simple example shows this:

cat file >file1 >file2
cat file1 file2

Here, it is possible that the second ‘cat’ will not display the full contents of file1 and file2 (i.e. the original contents of file repeated twice).

The reason for this is that the multios are spawned after the cat process is forked from the parent shell, so the parent shell does not wait for the multios to finish writing data. This means the command as shown can exit before file1 and file2 are completely written. As a workaround, it is possible to run the cat process as part of a job in the current shell:

{ cat file } >file >file2

Here, the {...} job will pause to wait for both files to be written.

REDIRECTIONS WITH NO COMMAND

When a simple command consists of one or more redirection operators and zero or more parameter assignments, but no command name, zsh can behave in several ways.

If the parameter NULLCMD is not set or the option CSH_NULLCMD is set, an error is caused. This is the csh behavior and CSH_NULLCMD is set by default when emulating csh.

If the option SH_NULLCMD is set, the builtin ‘:’ is inserted as a command with the given redirections. This is the default when emulating sh or ksh.

Otherwise, if the parameter NULLCMD is set, its value will be used as a command with the given redirections. If both NULLCMD and READNULLCMD are set, then the value of the latter will be used instead of that of the former when the redirection is an input. The default for NULLCMD is ‘cat’ and for READNULLCMD is ‘more’. Thus

< file

shows the contents of file on standard output, with paging if that is a terminal. NULLCMD and READNULLCMD may refer to shell functions.

COMMAND EXECUTION

If a command name contains no slashes, the shell attempts to locate it. If there exists a shell function by that name, the function is invoked as described in the section ‘Functions’. If there exists a shell builtin by that name, the builtin is invoked.

Otherwise, the shell searches each element of $path for a directory containing an executable file by that name. If the search is unsuccessful, the shell prints an error message and returns a nonzero exit status.

If execution fails because the file is not in executable format, and the file is not a directory, it is assumed to be a shell script. /bin/sh is spawned to execute it. If the program is a file beginning with ‘#!’, the remainder of the first line specifies an interpreter for the program. The shell will execute the specified interpreter on operating systems that do not handle this executable format in the kernel.

If no external command is found but a function command_not_found_handler exists the shell executes this function with all command line arguments. The function should return status zero if it successfully handled the command, or non-zero status if it failed. In the latter case the standard handling is applied: ‘command not found’ is printed to standard error and the shell exits with status 127. Note that the handler is executed in a subshell forked to execute an external command, hence changes to directories, shell parameters, etc. have no effect on the main shell.

FUNCTIONS

Shell functions are defined with the function reserved word or the special syntax ‘funcname ()’. Shell functions are read in and stored internally. Alias names are resolved when the function is read. Functions are executed like commands with the arguments passed as positional parameters. (See the section ‘Command Execution’.)

Functions execute in the same process as the caller and share all files and present working directory with the caller. A trap on EXIT set inside a function is executed after the function completes in the environment of the caller.

The return builtin is used to return from function calls.

Function identifiers can be listed with the functions builtin. Functions can be undefined with the unfunction builtin.

AUTOLOADING FUNCTIONS

A function can be marked as undefined using the autoload builtin (or ‘functions -u’ or ‘typeset -fu’). Such a function has no body. When the function is first executed, the shell searches for its definition using the elements of the fpath variable. Thus to define functions for autoloading, a typical sequence is:

fpath=(~/myfuncs $fpath)
autoload myfunc1 myfunc2 ...

The usual alias expansion during reading will be suppressed if the autoload builtin or its equivalent is given the option -U. This is recommended for the use of functions supplied with the zsh distribution. Note that for functions precompiled with the zcompile builtin command the flag -U must be provided when the .zwc file is created, as the corresponding information is compiled into the latter.

For each element in fpath, the shell looks for three possible files, the newest of which is used to load the definition for the function:

element.zwc
  A file created with the zcompile builtin command, which is expected to contain the definitions for all functions in the directory named element. The file is treated in the same manner as a directory containing files for functions and is searched for the definition of the function. If the definition is not found, the search for a definition proceeds with the other two possibilities described below.

If element already includes a .zwc extension (i.e. the extension was explicitly given by the user), element is searched for the definition of the function without comparing its age to that of other files; in fact, there does not need to be any directory named element without the suffix. Thus including an element such as ‘/usr/local/funcs.zwc’ in fpath will speed up the search for functions, with the disadvantage that functions included must be explicitly recompiled by hand before the shell notices any changes.

element/function.zwc
  A file created with zcompile, which is expected to contain the definition for function. It may include other function definitions as well, but those are neither loaded nor executed; a file found in this way is searched only for the definition of function.
element/function
  A file of zsh command text, taken to be the definition for function.
In summary, the order of searching is, first, in the parents of directories in fpath for the newer of either a compiled directory or a directory in fpath; second, if more than one of these contains a definition for the function that is sought, the leftmost in the fpath is chosen; and third, within a directory, the newer of either a compiled function or an ordinary function definition is used.
If the KSH_AUTOLOAD option is set, or the file contains only a simple definition of the function, the file’s contents will be executed. This will normally define the function in question, but may also perform initialization, which is executed in the context of the function execution, and may therefore define local parameters. It is an error if the function is not defined by loading the file.
Otherwise, the function body (with no surrounding ‘funcname() {...}’) is taken to be the complete contents of the file. This form allows the file to be used directly as an executable shell script. If processing of the file results in the function being re-defined, the function itself is not re-executed. To force the shell to perform initialization and then call the function defined, the file should contain initialization code (which will be executed then discarded) in addition to a complete function definition (which will be retained for subsequent calls to the function), and a call to the shell function, including any arguments, at the end.
For example, suppose the autoload file func contains

 
func() { print This is func; }
print func is initialized

then ‘func; func’ with KSH_AUTOLOAD set will produce both messages on the first call, but only the message ‘This is func’ on the second and subsequent calls. Without KSH_AUTOLOAD set, it will produce the initialization message on the first call, and the other message on the second and subsequent calls.
It is also possible to create a function that is not marked as autoloaded, but which loads its own definition by searching fpath, by using ‘autoload -X’ within a shell function. For example, the following are equivalent:

 
myfunc() {
  autoload -X
}
myfunc args...

and

 
unfunction myfunc   # if myfunc was defined
autoload myfunc
myfunc args...

In fact, the functions command outputs ‘builtin autoload -X’ as the body of an autoloaded function. This is done so that

 
eval "$(functions)"

produces a reasonable result. A true autoloaded function can be identified by the presence of the comment ‘# undefined’ in the body, because all comments are discarded from defined functions.
To load the definition of an autoloaded function myfunc without executing myfunc, use:

 
autoload +X myfunc

ANONYMOUS FUNCTIONS

If no name is given for a function, it is ‘anonymous’ and is handled specially. Either form of function definition may be used: a ‘()’ with no preceding name, or a ‘function’ with an immediately following open brace. The function is executed immediately at the point of definition and is not stored for future use. The function name is set to ‘(anon)’.

Arguments to the function may be specified as words following the closing brace defining the function, hence if there are none no arguments (other than $0) are set. This is a difference from the way other functions are parsed: normal function definitions may be followed by certain keywords such as ‘else’ or ‘fi’, which will be treated as arguments to anonymous functions, so that a newline or semicolon is needed to force keyword interpretation.

Note also that the argument list of any enclosing script or function is hidden (as would be the case for any other function called at this point).

Redirections may be applied to the anonymous function in the same manner as to a current-shell structure enclosed in braces. The main use of anonymous functions is to provide a scope for local variables. This is particularly convenient in start-up files as these do not provide their own local variable scope.

For example,

variable=outside
function {
  local variable=inside
  print "I am $variable with arguments $*"
} this and that
print "I am $variable"

outputs the following:

I am inside with arguments this and that
I am outside

Note that function definitions with arguments that expand to nothing, for example ‘name=; function $name { ... }’, are not treated as anonymous functions. Instead, they are treated as normal function definitions where the definition is silently discarded.

SPECIAL FUNCTIONS

Certain functions, if defined, have special meaning to the shell.

    Hook Functions

For the functions below, it is possible to define an array that has the same name as the function with ‘_functions’ appended. Any element in such an array is taken as the name of a function to execute; it is executed in the same context and with the same arguments as the basic function. For example, if $chpwd_functions is an array containing the values ‘mychpwd’, ‘chpwd_save_dirstack’, then the shell attempts to execute the functions ‘chpwd’, ‘mychpwd’ and ‘chpwd_save_dirstack’, in that order. Any function that does not exist is silently ignored. A function found by this mechanism is referred to elsewhere as a ‘hook function’. An error in any function causes subsequent functions not to be run. Note further that an error in a precmd hook causes an immediately following periodic function not to run (though it may run at the next opportunity).

chpwd Executed whenever the current working directory is changed.
periodic
  If the parameter PERIOD is set, this function is executed every $PERIOD seconds, just before a prompt. Note that if multiple functions are defined using the array periodic_functions only one period is applied to the complete set of functions, and the scheduled time is not reset if the list of functions is altered. Hence the set of functions is always called together.
precmd Executed before each prompt. Note that precommand functions are not re-executed simply because the command line is redrawn, as happens, for example, when a notification about an exiting job is displayed.
preexec
  Executed just after a command has been read and is about to be executed. If the history mechanism is active (regardless of whether the line was discarded from the history buffer), the string that the user typed is passed as the first argument, otherwise it is an empty string. The actual command that will be executed (including expanded aliases) is passed in two different forms: the second argument is a single-line, size-limited version of the command (with things like function bodies elided); the third argument contains the full text that is being executed.
zshaddhistory
  Executed when a history line has been read interactively, but before it is executed. The sole argument is the complete history line (so that any terminating newline will still be present).

If any of the hook functions returns status 1 (or any non-zero value other than 2, though this is not guaranteed for future versions of the shell) the history line will not be saved, although it lingers in the history until the next line is executed, allowing you to reuse or edit it immediately.

If any of the hook functions returns status 2 the history line will be saved on the internal history list, but not written to the history file. In case of a conflict, the first non-zero status value is taken.

A hook function may call ‘fc -p ...’ to switch the history context so that the history is saved in a different file from the that in the global HISTFILE parameter. This is handled specially: the history context is automatically restored after the processing of the history line is finished.

The following example function works with one of the options INC_APPEND_HISTORY or SHARE_HISTORY set, in order that the line is written out immediately after the history entry is added. It first adds the history line to the normal history with the newline stripped, which is usually the correct behaviour. Then it switches the history context so that the line will be written to a history file in the current directory.

 
zshaddhistory() {
  print -sr -- ${1%%$’\n’}
  fc -p .zsh_local_history
}

zshexit
  Executed at the point where the main shell is about to exit normally. This is not called by exiting subshells, nor when the exec precommand modifier is used before an external command. Also, unlike TRAPEXIT, it is not called when functions exit.

    Trap Functions

The functions below are treated specially but do not have corresponding hook arrays.

TRAPNAL
  If defined and non-null, this function will be executed whenever the shell catches a signal SIGNAL, where NAL is a signal name as specified for the kill builtin. The signal number will be passed as the first parameter to the function.

If a function of this form is defined and null, the shell and processes spawned by it will ignore SIGNAL.

The return status from the function is handled specially. If it is zero, the signal is assumed to have been handled, and execution continues normally. Otherwise, the shell will behave as interrupted except that the return status of the trap is retained.

Programs terminated by uncaught signals typically return the status 128 plus the signal number. Hence the following causes the handler for SIGINT to print a message, then mimic the usual effect of the signal.

 
TRAPINT() {
  print "Caught SIGINT, aborting."
  return $(( 128 + $1 ))
}

The functions TRAPZERR, TRAPDEBUG and TRAPEXIT are never executed inside other traps.

TRAPDEBUG
  If the option DEBUG_BEFORE_CMD is set (as it is by default), executed before each command; otherwise executed after each command. See the description of the trap builtin in zshbuiltins(1) for details of additional features provided in debug traps.
TRAPEXIT
  Executed when the shell exits, or when the current function exits if defined inside a function. The value of $? at the start of execution is the exit status of the shell or the return status of the function exiting.
TRAPZERR
  Executed whenever a command has a non-zero exit status. However, the function is not executed if the command occurred in a sublist followed by ‘&&’ or ‘||’; only the final command in a sublist of this type causes the trap to be executed. The function TRAPERR acts the same as TRAPZERR on systems where there is no SIGERR (this is the usual case).
The functions beginning ‘TRAP’ may alternatively be defined with the trap builtin: this may be preferable for some uses. Setting a trap with one form removes any trap of the other form for the same signal; removing a trap in either form removes all traps for the same signal. The forms

 
TRAPNAL() {
 # code
}

(’function traps’) and

 
trap ’
 # code
’ NAL

(’list traps’) are equivalent in most ways, the exceptions being the following:
o Function traps have all the properties of normal functions, appearing in the list of functions and being called with their own function context rather than the context where the trap was triggered.
o The return status from function traps is special, whereas a return from a list trap causes the surrounding context to return with the given status.
o Function traps are not reset within subshells, in accordance with zsh behaviour; list traps are reset, in accordance with POSIX behaviour.

JOBS

If the MONITOR option is set, an interactive shell associates a job with each pipeline. It keeps a table of current jobs, printed by the jobs command, and assigns them small integer numbers. When a job is started asynchronously with ‘&’, the shell prints a line to standard error which looks like:

[1] 1234

indicating that the job which was started asynchronously was job number 1 and had one (top-level) process, whose process ID was 1234.

If a job is started with ‘&|’ or ‘&!’, then that job is immediately disowned. After startup, it does not have a place in the job table, and is not subject to the job control features described here.

If you are running a job and wish to do something else you may hit the key ^Z (control-Z) which sends a TSTP signal to the current job: this key may be redefined by the susp option of the external stty command. The shell will then normally indicate that the job has been ‘suspended’, and print another prompt. You can then manipulate the state of this job, putting it in the background with the bg command, or run some other commands and then eventually bring the job back into the foreground with the foreground command fg. A ^Z takes effect immediately and is like an interrupt in that pending output and unread input are discarded when it is typed.

A job being run in the background will suspend if it tries to read from the terminal.

Note that if the job running in the foreground is a shell function, then suspending it will have the effect of causing the shell to fork. This is necessary to separate the function’s state from that of the parent shell performing the job control, so that the latter can return to the command line prompt. As a result, even if fg is used to continue the job the function will no longer be part of the parent shell, and any variables set by the function will not be visible in the parent shell. Thus the behaviour is different from the case where the function was never suspended. Zsh is different from many other shells in this regard.

The same behaviour is found when the shell is executing code as the right hand side of a pipeline or any complex shell construct such as if, for, etc., in order that the entire block of code can be managed as a single job. Background jobs are normally allowed to produce output, but this can be disabled by giving the command ‘stty tostop’. If you set this tty option, then background jobs will suspend when they try to produce output like they do when they try to read input.

When a command is suspended and continued later with the fg or wait builtins, zsh restores tty modes that were in effect when it was suspended. This (intentionally) does not apply if the command is continued via ‘kill -CONT’, nor when it is continued with bg.

There are several ways to refer to jobs in the shell. A job can be referred to by the process ID of any process of the job or by one of the following:

%number
  The job with the given number.
%string
  Any job whose command line begins with string.
%?string
  Any job whose command line contains string.
%% Current job.
%+ Equivalent to ‘%%’.
%- Previous job.
The shell learns immediately whenever a process changes state. It normally informs you whenever a job becomes blocked so that no further progress is possible. If the NOTIFY option is not set, it waits until just before it prints a prompt before it informs you. All such notifications are sent directly to the terminal, not to the standard output or standard error.

When the monitor mode is on, each background job that completes triggers any trap set for CHLD.

When you try to leave the shell while jobs are running or suspended, you will be warned that ‘You have suspended (running) jobs’. You may use the jobs command to see what they are. If you do this or immediately try to exit again, the shell will not warn you a second time; the suspended jobs will be terminated, and the running jobs will be sent a SIGHUP signal, if the HUP option is set.

To avoid having the shell terminate the running jobs, either use the nohup command (see nohup(1)) or the disown builtin.

SIGNALS

The INT and QUIT signals for an invoked command are ignored if the command is followed by ‘&’ and the MONITOR option is not active. The shell itself always ignores the QUIT signal. Otherwise, signals have the values inherited by the shell from its parent (but see the TRAPNAL special functions in the section ‘Functions’).

Certain jobs are run asynchronously by the shell other than those explicitly put into the background; even in cases where the shell would usually wait for such jobs, an explicit exit command or exit due to the option ERR_EXIT will cause the shell to exit without waiting. Examples of such asynchronous jobs are process substitution, see the section PROCESS SUBSTITUTION in the zshexpn(1) manual page, and the handler processes for multios, see the section MULTIOS in the zshmisc(1) manual page.

ARITHMETIC EVALUATION

The shell can perform integer and floating point arithmetic, either using the builtin let, or via a substitution of the form $((...)). For integers, the shell is usually compiled to use 8-byte precision where this is available, otherwise precision is 4 bytes. This can be tested, for example, by giving the command ‘print - $(( 12345678901 ))’; if the number appears unchanged, the precision is at least 8 bytes. Floating point arithmetic always uses the ‘double’ type with whatever corresponding precision is provided by the compiler and the library.

The let builtin command takes arithmetic expressions as arguments; each is evaluated separately. Since many of the arithmetic operators, as well as spaces, require quoting, an alternative form is provided: for any command which begins with a ‘((’, all the characters until a matching ‘))’ are treated as a quoted expression and arithmetic expansion performed as for an argument of let. More precisely, ‘((...))’ is equivalent to ‘let "..."’. The return status is 0 if the arithmetic value of the expression is non-zero, 1 if it is zero, and 2 if an error occurred.

For example, the following statement

(( val = 2 + 1 ))

is equivalent to

let "val = 2 + 1"

both assigning the value 3 to the shell variable val and returning a zero status.

Integers can be in bases other than 10. A leading ‘0x’ or ‘0X’ denotes hexadecimal and a leading ‘0b’ or ‘0B’ binary. Integers may also be of the form ‘base#n’, where base is a decimal number between two and thirty-six representing the arithmetic base and n is a number in that base (for example, ‘16#ff’ is 255 in hexadecimal). The base# may also be omitted, in which case base 10 is used. For backwards compatibility the form ‘[base]n’ is also accepted.

An integer expression or a base given in the form ‘base#n’ may contain underscores (‘_’) after the leading digit for visual guidance; these are ignored in computation. Examples are 1_000_000 or 0xffff_ffff which are equivalent to 1000000 and 0xffffffff respectively.

It is also possible to specify a base to be used for output in the form ‘[#base]’, for example ‘[#16]’. This is used when outputting arithmetical substitutions or when assigning to scalar parameters, but an explicitly defined integer or floating point parameter will not be affected. If an integer variable is implicitly defined by an arithmetic expression, any base specified in this way will be set as the variable’s output arithmetic base as if the option ‘-i base’ to the typeset builtin had been used. The expression has no precedence and if it occurs more than once in a mathematical expression, the last encountered is used. For clarity it is recommended that it appear at the beginning of an expression. As an example:

typeset -i 16 y
print $(( [#8] x = 32, y = 32 ))
print $x $y

outputs first ‘8#40’, the rightmost value in the given output base, and then ‘8#40 16#20’, because y has been explicitly declared to have output base 16, while x (assuming it does not already exist) is implicitly typed by the arithmetic evaluation, where it acquires the output base 8.

The base may be replaced or followed by an underscore, which may itself be followed by a positive integer (if it is missing the value 3 is used). This indicates that underscores should be inserted into the output string, grouping the number for visual clarity. The following integer specifies the number of digits to group together. For example:

setopt cbases
print $(( [#16_4] 65536 ** 2 ))

outputs ‘0x1_0000_0000’.

The feature can be used with floating point numbers, in which case the base must be omitted; grouping is away from the decimal point. For example,

zmodload zsh/mathfunc
print $(( [#_] sqrt(1e7) ))

outputs ‘3_162.277_660_168_379_5’ (the number of decimal places shown may vary).

If the C_BASES option is set, hexadecimal numbers are output in the standard C format, for example ‘0xFF’ instead of the usual ‘16#FF’. If the option OCTAL_ZEROES is also set (it is not by default), octal numbers will be treated similarly and hence appear as ‘077’ instead of ‘8#77’. This option has no effect on the output of bases other than hexadecimal and octal, and these formats are always understood on input.

When an output base is specified using the ‘[#base]’ syntax, an appropriate base prefix will be output if necessary, so that the value output is valid syntax for input. If the # is doubled, for example ‘[##16]’, then no base prefix is output.

Floating point constants are recognized by the presence of a decimal point or an exponent. The decimal point may be the first character of the constant, but the exponent character e or E may not, as it will be taken for a parameter name. All numeric parts (before and after the decimal point and in the exponent) may contain underscores after the leading digit for visual guidance; these are ignored in computation.

An arithmetic expression uses nearly the same syntax and associativity of expressions as in C.

In the native mode of operation, the following operators are supported (listed in decreasing order of precedence):

+ - ! ~ ++ --
  unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement
<< >> bitwise shift left, right
& bitwise AND
^ bitwise XOR
| bitwise OR
** exponentiation
* / % multiplication, division, modulus (remainder)
+ - addition, subtraction
< > <= >=
  comparison
== != equality and inequality
&& logical AND
|| ^^ logical OR, XOR
? : ternary operator
= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
  assignment
, comma operator
The operators ‘&&’, ‘||’, ‘&&=’, and ‘||=’ are short-circuiting, and only one of the latter two expressions in a ternary operator is evaluated. Note the precedence of the bitwise AND, OR, and XOR operators.
With the option C_PRECEDENCES the precedences (but no other properties) of the operators are altered to be the same as those in most other languages that support the relevant operators:
+ - ! ~ ++ --
  unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement
** exponentiation
* / % multiplication, division, modulus (remainder)
+ - addition, subtraction
<< >> bitwise shift left, right
< > <= >=
  comparison
== != equality and inequality
& bitwise AND
^ bitwise XOR
| bitwise OR
&& logical AND
^^ logical XOR
|| logical OR
? : ternary operator
= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
  assignment
, comma operator
Note the precedence of exponentiation in both cases is below that of unary operators, hence ‘-3**2’ evaluates as ‘9’, not ‘-9’. Use parentheses where necessary: ‘-(3**2)’. This is for compatibility with other shells.
Mathematical functions can be called with the syntax ‘func(args)’, where the function decides if the args is used as a string or a comma-separated list of arithmetic expressions. The shell currently defines no mathematical functions by default, but the module zsh/mathfunc may be loaded with the zmodload builtin to provide standard floating point mathematical functions.
An expression of the form ‘##x’ where x is any character sequence such as ‘a’, ‘^A’, or ‘\M-\C-x’ gives the value of this character and an expression of the form ‘#name’ gives the value of the first character of the contents of the parameter name. Character values are according to the character set used in the current locale; for multibyte character handling the option MULTIBYTE must be set. Note that this form is different from ‘$#name’, a standard parameter substitution which gives the length of the parameter name. ‘#\’ is accepted instead of ‘##’, but its use is deprecated.
Named parameters and subscripted arrays can be referenced by name within an arithmetic expression without using the parameter expansion syntax. For example,

 
((val2 = val1 * 2))

assigns twice the value of $val1 to the parameter named val2.
An internal integer representation of a named parameter can be specified with the integer builtin. Arithmetic evaluation is performed on the value of each assignment to a named parameter declared integer in this manner. Assigning a floating point number to an integer results in rounding towards zero.
Likewise, floating point numbers can be declared with the float builtin; there are two types, differing only in their output format, as described for the typeset builtin. The output format can be bypassed by using arithmetic substitution instead of the parameter substitution, i.e. ‘${float}’ uses the defined format, but ‘$((float))’ uses a generic floating point format.
Promotion of integer to floating point values is performed where necessary. In addition, if any operator which requires an integer (‘&’, ‘|’, ‘^’, ‘<<’, ‘>>’ and their equivalents with assignment) is given a floating point argument, it will be silently rounded towards zero except for ‘~’ which rounds down.
Users should beware that, in common with many other programming languages but not software designed for calculation, the evaluation of an expression in zsh is taken a term at a time and promotion of integers to floating point does not occur in terms only containing integers. A typical result of this is that a division such as 6/8 is truncated, in this being rounded towards 0. The FORCE_FLOAT shell option can be used in scripts or functions where floating point evaluation is required throughout.
Scalar variables can hold integer or floating point values at different times; there is no memory of the numeric type in this case.
If a variable is first assigned in a numeric context without previously being declared, it will be implicitly typed as integer or float and retain that type either until the type is explicitly changed or until the end of the scope. This can have unforeseen consequences. For example, in the loop

 
for (( f = 0; f < 1; f += 0.1 )); do
# use $f
done

if f has not already been declared, the first assignment will cause it to be created as an integer, and consequently the operation ‘f += 0.1’ will always cause the result to be truncated to zero, so that the loop will fail. A simple fix would be to turn the initialization into ‘f = 0.0’. It is therefore best to declare numeric variables with explicit types.

CONDITIONAL EXPRESSIONS

A conditional expression is used with the [[ compound command to test attributes of files and to compare strings. Each expression can be constructed from one or more of the following unary or binary expressions:

-a file true if file exists.
-b file true if file exists and is a block special file.
-c file true if file exists and is a character special file.
-d file true if file exists and is a directory.
-e file true if file exists.
-f file true if file exists and is a regular file.
-g file true if file exists and has its setgid bit set.
-h file true if file exists and is a symbolic link.
-k file true if file exists and has its sticky bit set.
-n string
  true if length of string is non-zero.
-o option
  true if option named option is on. option may be a single character, in which case it is a single letter option name. (See the section ‘Specifying Options’.)
-p file true if file exists and is a FIFO special file (named pipe).
-r file true if file exists and is readable by current process.
-s file true if file exists and has size greater than zero.
-t fd true if file descriptor number fd is open and associated with a terminal device. (note: fd is not optional)
-u file true if file exists and has its setuid bit set.
-w file true if file exists and is writable by current process.
-x file true if file exists and is executable by current process. If file exists and is a directory, then the current process has permission to search in the directory.
-z string
  true if length of string is zero.
-L file true if file exists and is a symbolic link.
-O file true if file exists and is owned by the effective user ID of this process.
-G file true if file exists and its group matches the effective group ID of this process.
-S file true if file exists and is a socket.
-N file true if file exists and its access time is not newer than its modification time.
file1 -nt file2
  true if file1 exists and is newer than file2.
file1 -ot file2
  true if file1 exists and is older than file2.
file1 -ef file2
  true if file1 and file2 exist and refer to the same file.
string = pattern
string == pattern
  true if string matches pattern. The ‘==’ form is the preferred one. The ‘=’ form is for backward compatibility and should be considered obsolete.
string != pattern
  true if string does not match pattern.
string =~ regexp
  true if string matches the regular expression regexp. If the option RE_MATCH_PCRE is set regexp is tested as a PCRE regular expression using the zsh/pcre module, else it is tested as a POSIX extended regular expression using the zsh/regex module. Upon successful match, some variables will be updated; no variables are changed if the matching fails.

If the option BASH_REMATCH is not set the scalar parameter MATCH is set to the substring that matched the pattern and the integer parameters MBEGIN and MEND to the index of the start and end, respectively, of the match in string, such that if string is contained in variable var the expression ‘${var[$MBEGIN,$MEND]}’ is identical to ‘$MATCH’. The setting of the option KSH_ARRAYS is respected. Likewise, the array match is set to the substrings that matched parenthesised subexpressions and the arrays mbegin and mend to the indices of the start and end positions, respectively, of the substrings within string. The arrays are not set if there were no parenthesised subexpresssions. For example, if the string ‘a short string’ is matched against the regular expression ‘s(...)t’, then (assuming the option KSH_ARRAYS is not set) MATCH, MBEGIN and MEND are ‘short’, 3 and 7, respectively, while match, mbegin and mend are single entry arrays containing the strings ‘hor’, ‘4’ and ‘6’, respectively.

If the option BASH_REMATCH is set the array BASH_REMATCH is set to the substring that matched the pattern followed by the substrings that matched parenthesised subexpressions within the pattern.

string1 < string2
  true if string1 comes before string2 based on ASCII value of their characters.
string1 > string2
  true if string1 comes after string2 based on ASCII value of their characters.
exp1 -eq exp2
  true if exp1 is numerically equal to exp2. Note that for purely numeric comparisons use of the ((...)) builtin described in the section ‘ARITHMETIC EVALUATION’ is more convenient than conditional expressions.
exp1 -ne exp2
  true if exp1 is numerically not equal to exp2.
exp1 -lt exp2
  true if exp1 is numerically less than exp2.
exp1 -gt exp2
  true if exp1 is numerically greater than exp2.
exp1 -le exp2
  true if exp1 is numerically less than or equal to exp2.
exp1 -ge exp2
  true if exp1 is numerically greater than or equal to exp2.
( exp ) true if exp is true.
! exp true if exp is false.
exp1 && exp2
  true if exp1 and exp2 are both true.
exp1 || exp2
  true if either exp1 or exp2 is true.
For compatibility, if there is a single argument that is not syntactically significant, typically a variable, the condition is treated as a test for whether the expression expands as a string of non-zero length. In other words, [[ $var ]] is the same as [[ -n $var ]]. It is recommended that the second, explicit, form be used where possible.
Normal shell expansion is performed on the file, string and pattern arguments, but the result of each expansion is constrained to be a single word, similar to the effect of double quotes.
Filename generation is not performed on any form of argument to conditions. However, it can be forced in any case where normal shell expansion is valid and when the option EXTENDED_GLOB is in effect by using an explicit glob qualifier of the form (#q) at the end of the string. A normal glob qualifier expression may appear between the ‘q’ and the closing parenthesis; if none appears the expression has no effect beyond causing filename generation. The results of filename generation are joined together to form a single word, as with the results of other forms of expansion.
This special use of filename generation is only available with the [[ syntax. If the condition occurs within the [ or test builtin commands then globbing occurs instead as part of normal command line expansion before the condition is evaluated. In this case it may generate multiple words which are likely to confuse the syntax of the test command.
For example,

 
[[ -n file*(#qN) ]]

produces status zero if and only if there is at least one file in the current directory beginning with the string ‘file’. The globbing qualifier N ensures that the expression is empty if there is no matching file.
Pattern metacharacters are active for the pattern arguments; the patterns are the same as those used for filename generation, see zshexpn(1), but there is no special behaviour of ‘/’ nor initial dots, and no glob qualifiers are allowed.
In each of the above expressions, if file is of the form ‘/dev/fd/n’, where n is an integer, then the test applied to the open file whose descriptor number is n, even if the underlying system does not support the /dev/fd directory.
In the forms which do numeric comparison, the expressions exp undergo arithmetic expansion as if they were enclosed in $((...)).
For example, the following:

 
[[ ( -f foo || -f bar ) && $report = y* ]] && print File exists.

tests if either file foo or file bar exists, and if so, if the value of the parameter report begins with ‘y’; if the complete condition is true, the message ‘File exists.’ is printed.

EXPANSION OF PROMPT SEQUENCES

Prompt sequences undergo a special form of expansion. This type of expansion is also available using the -P option to the print builtin.

If the PROMPT_SUBST option is set, the prompt string is first subjected to parameter expansion, command substitution and arithmetic expansion. See zshexpn(1).

Certain escape sequences may be recognised in the prompt string.

If the PROMPT_BANG option is set, a ‘!’ in the prompt is replaced by the current history event number. A literal ‘!’ may then be represented as ‘!!’.

If the PROMPT_PERCENT option is set, certain escape sequences that start with ‘%’ are expanded. Many escapes are followed by a single character, although some of these take an optional integer argument that should appear between the ‘%’ and the next character of the sequence. More complicated escape sequences are available to provide conditional expansion.

SIMPLE PROMPT ESCAPES

    Special characters

%% A ‘%’.
%) A ‘)’.

    Login information

%l The line (tty) the user is logged in on, without ‘/dev/’ prefix. If the name starts with ‘/dev/tty’, that prefix is stripped.
%M The full machine hostname.
%m The hostname up to the first ‘.’. An integer may follow the ‘%’ to specify how many components of the hostname are desired. With a negative integer, trailing components of the hostname are shown.
%n $USERNAME.
%y The line (tty) the user is logged in on, without ‘/dev/’ prefix. This does not treat ‘/dev/tty’ names specially.

    Shell state

%# A ‘#’ if the shell is running with privileges, a ‘%’ if not. Equivalent to ‘%(!.#.%%)’. The definition of ‘privileged’, for these purposes, is that either the effective user ID is zero, or, if POSIX.1e capabilities are supported, that at least one capability is raised in either the Effective or Inheritable capability vectors.
%? The return status of the last command executed just before the prompt.
%_ The status of the parser, i.e. the shell constructs (like ‘if’ and ‘for’) that have been started on the command line. If given an integer number that many strings will be printed; zero or negative or no integer means print as many as there are. This is most useful in prompts PS2 for continuation lines and PS4 for debugging with the XTRACE option; in the latter case it will also work non-interactively.
%^ The status of the parser in reverse. This is the same as ‘%_’ other than the order of strings. It is often used in RPS2.
%d
%/
Current working directory. If an integer follows the ‘%’, it specifies a number of trailing components of the current working directory to show; zero means the whole path. A negative integer specifies leading components, i.e. %-1d specifies the first component.
%~ As %d and %/, but if the current working directory starts with $HOME, that part is replaced by a ‘~’. Furthermore, if it has a named directory as its prefix, that part is replaced by a ‘~’ followed by the name of the directory, but only if the result is shorter than the full path; see Dynamic and Static named directories in zshexpn(1).
%e Evaluation depth of the current sourced file, shell function, or eval. This is incremented or decremented every time the value of %N is set or reverted to a previous value, respectively. This is most useful for debugging as part of $PS4.
%h
%!
Current history event number.
%i The line number currently being executed in the script, sourced file, or shell function given by %N. This is most useful for debugging as part of $PS4.
%I The line number currently being executed in the file %x. This is similar to %i, but the line number is always a line number in the file where the code was defined, even if the code is a shell function.
%j The number of jobs.
%L The current value of $SHLVL.
%N The name of the script, sourced file, or shell function that zsh is currently executing, whichever was started most recently. If there is none, this is equivalent to the parameter $0. An integer may follow the ‘%’ to specify a number of trailing path components to show; zero means the full path. A negative integer specifies leading components.
%x The name of the file containing the source code currently being executed. This behaves as %N except that function and eval command names are not shown, instead the file where they were defined.
%c
%.
%C
Trailing component of the current working directory. An integer may follow the ‘%’ to get more than one component. Unless ‘%C’ is used, tilde contraction is performed first. These are deprecated as %c and %C are equivalent to %1~ and %1/, respectively, while explicit positive integers have the same effect as for the latter two sequences.

    Date and time

%D The date in yy-mm-dd format.
%T Current time of day, in 24-hour format.
%t
%@
Current time of day, in 12-hour, am/pm format.
%* Current time of day in 24-hour format, with seconds.
%w The date in day-dd format.
%W The date in mm/dd/yy format.
%D{string}
  string is formatted using the strftime function. See strftime(3) for more details. Various zsh extensions provide numbers with no leading zero or space if the number is a single digit:

%f a day of the month
%K the hour of the day on the 24-hour clock
%L the hour of the day on the 12-hour clock
In addition, if the system supports the POSIX gettimeofday system call, %. provides decimal fractions of a second since the epoch with leading zeroes. By default three decimal places are provided, but a number of digits up to 6 may be given following the %; hence %6. outputs microseconds. A typical example of this is the format ‘%D{%H:%M:%S.%.}’.

The GNU extension that a ‘-’ between the % and the format character causes a leading zero or space to be stripped is handled directly by the shell for the format characters d, f, H, k, l, m, M, S and y; any other format characters are provided to the system’s strftime(3) with any leading ‘-’ present, so the handling is system dependent. Further GNU (or other) extensions are also passed to strftime(3) and may work if the system supports them.

    Visual effects

%B (%b) Start (stop) boldface mode.
%E Clear to end of line.
%U (%u) Start (stop) underline mode.
%S (%s) Start (stop) standout mode.
%F (%f) Start (stop) using a different foreground colour, if supported by the terminal. The colour may be specified two ways: either as a numeric argument, as normal, or by a sequence in braces following the %F, for example %F{red}. In the latter case the values allowed are as described for the fg zle_highlight attribute; see Character Highlighting in zshzle(1). This means that numeric colours are allowed in the second format also.
%K (%k) Start (stop) using a different bacKground colour. The syntax is identical to that for %F and %f.
%{...%} Include a string as a literal escape sequence. The string within the braces should not change the cursor position. Brace pairs can nest.

A positive numeric argument between the % and the { is treated as described for %G below.

%G Within a %{...%} sequence, include a ‘glitch’: that is, assume that a single character width will be output. This is useful when outputting characters that otherwise cannot be correctly handled by the shell, such as the alternate character set on some terminals. The characters in question can be included within a %{...%} sequence together with the appropriate number of %G sequences to indicate the correct width. An integer between the ‘%’ and ‘G’ indicates a character width other than one. Hence %{seq%2G%} outputs seq and assumes it takes up the width of two standard characters.

Multiple uses of %G accumulate in the obvious fashion; the position of the %G is unimportant. Negative integers are not handled.

Note that when prompt truncation is in use it is advisable to divide up output into single characters within each %{...%} group so that the correct truncation point can be found.

CONDITIONAL SUBSTRINGS IN PROMPTS

%v The value of the first element of the psvar array parameter. Following the ‘%’ with an integer gives that element of the array. Negative integers count from the end of the array.
%(x.true-text.false-text)
  Specifies a ternary expression. The character following the x is arbitrary; the same character is used to separate the text for the ‘true’ result from that for the ‘false’ result. This separator may not appear in the true-text, except as part of a %-escape sequence. A ‘)’ may appear in the false-text as ‘%)’. true-text and false-text may both contain arbitrarily-nested escape sequences, including further ternary expressions.

The left parenthesis may be preceded or followed by a positive integer n, which defaults to zero. A negative integer will be multiplied by -1, except as noted below for ‘l’. The test character x may be any of the following:

! True if the shell is running with privileges.
# True if the effective uid of the current process is n.
? True if the exit status of the last command was n.
_ True if at least n shell constructs were started.
C
/
True if the current absolute path has at least n elements relative to the root directory, hence / is counted as 0 elements.
c
.
~
True if the current path, with prefix replacement, has at least n elements relative to the root directory, hence / is counted as 0 elements.
D True if the month is equal to n (January = 0).
d True if the day of the month is equal to n.
e True if the evaluation depth is at least n.
g True if the effective gid of the current process is n.
j True if the number of jobs is at least n.
L True if the SHLVL parameter is at least n.
l True if at least n characters have already been printed on the current line. When n is negative, true if at least abs(n) characters remain before the opposite margin (thus the left margin for RPROMPT).
S True if the SECONDS parameter is at least n.
T True if the time in hours is equal to n.
t True if the time in minutes is equal to n.
v True if the array psvar has at least n elements.
V True if element n of the array psvar is set and non-empty.
w True if the day of the week is equal to n (Sunday = 0).

%<string<
%>string>
%[xstring]
  Specifies truncation behaviour for the remainder of the prompt string. The third, deprecated, form is equivalent to ‘%xstringx’, i.e. x may be ‘<’ or ‘>’. The string will be displayed in place of the truncated portion of any string; note this does not undergo prompt expansion.

The numeric argument, which in the third form may appear immediately after the ‘[’, specifies the maximum permitted length of the various strings that can be displayed in the prompt. In the first two forms, this numeric argument may be negative, in which case the truncation length is determined by subtracting the absolute value of the numeric argument from the number of character positions remaining on the current prompt line. If this results in a zero or negative length, a length of 1 is used. In other words, a negative argument arranges that after truncation at least n characters remain before the right margin (left margin for RPROMPT).

The forms with ‘<’ truncate at the left of the string, and the forms with ‘>’ truncate at the right of the string. For example, if the current directory is ‘/home/pike’, the prompt ‘%8<..<%/’ will expand to ‘..e/pike’. In this string, the terminating character (‘<’, ‘>’ or ‘]’), or in fact any character, may be quoted by a preceding ‘\’; note when using print -P, however, that this must be doubled as the string is also subject to standard print processing, in addition to any backslashes removed by a double quoted string: the worst case is therefore ‘print -P "%<\\\\<<..."’.

If the string is longer than the specified truncation length, it will appear in full, completely replacing the truncated string.

The part of the prompt string to be truncated runs to the end of the string, or to the end of the next enclosing group of the ‘%(’ construct, or to the next truncation encountered at the same grouping level (i.e. truncations inside a ‘%(’ are separate), which ever comes first. In particular, a truncation with argument zero (e.g., ‘%<<’) marks the end of the range of the string to be truncated while turning off truncation from there on. For example, the prompt ‘%10<...<%~%<<%# ’ will print a truncated representation of the current directory, followed by a ‘%’ or ‘#’, followed by a space. Without the ‘%<<’, those two characters would be included in the string to be truncated. Note that ‘%-0<<’ is not equivalent to ‘%<<’ but specifies that the prompt is truncated at the right margin.

Truncation applies only within each individual line of the prompt, as delimited by embedded newlines (if any). If the total length of any line of the prompt after truncation is greater than the terminal width, or if the part to be truncated contains embedded newlines, truncation behavior is undefined and may change in a future version of the shell. Use ‘%-n(l.true-text.false-text)’ to remove parts of the prompt when the available space is less than n.

NAME

zshexpn - zsh expansion and substitution

DESCRIPTION

The following types of expansions are performed in the indicated order in five steps:

History Expansion
  This is performed only in interactive shells.
Alias Expansion
  Aliases are expanded immediately before the command line is parsed as explained under Aliasing in zshmisc(1).
Process Substitution
Parameter Expansion
Command Substitution
Arithmetic Expansion
Brace Expansion
  These five are performed in one step in left-to-right fashion. After these expansions, all unquoted occurrences of the characters ‘\’, ‘’ and ‘"’ are removed.
Filename Expansion
  If the SH_FILE_EXPANSION option is set, the order of expansion is modified for compatibility with sh and ksh. In that case filename expansion is performed immediately after alias expansion, preceding the set of five expansions mentioned above.
Filename Generation
  This expansion, commonly referred to as globbing, is always done last.
The following sections explain the types of expansion in detail.

HISTORY EXPANSION

History expansion allows you to use words from previous command lines in the command line you are typing. This simplifies spelling corrections and the repetition of complicated commands or arguments.

Immediately before execution, each command is saved in the history list, the size of which is controlled by the HISTSIZE parameter. The one most recent command is always retained in any case. Each saved command in the history list is called a history event and is assigned a number, beginning with 1 (one) when the shell starts up. The history number that you may see in your prompt (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)) is the number that is to be assigned to the next command.

    Overview

A history expansion begins with the first character of the histchars parameter, which is ‘!’ by default, and may occur anywhere on the command line; history expansions do not nest. The ‘!’ can be escaped with ‘\’ or can be enclosed between a pair of single quotes (’’) to suppress its special meaning. Double quotes will not work for this. Following this history character is an optional event designator (see the section ‘Event Designators’) and then an optional word designator (the section ‘Word Designators’); if neither of these designators is present, no history expansion occurs.

Input lines containing history expansions are echoed after being expanded, but before any other expansions take place and before the command is executed. It is this expanded form that is recorded as the history event for later references.

By default, a history reference with no event designator refers to the same event as any preceding history reference on that command line; if it is the only history reference in a command, it refers to the previous command. However, if the option CSH_JUNKIE_HISTORY is set, then every history reference with no event specification always refers to the previous command.

For example, ‘!’ is the event designator for the previous command, so ‘!!:1’ always refers to the first word of the previous command, and ‘!!$’ always refers to the last word of the previous command. With CSH_JUNKIE_HISTORY set, then ‘!:1’ and ‘!$’ function in the same manner as ‘!!:1’ and ‘!!$’, respectively. Conversely, if CSH_JUNKIE_HISTORY is unset, then ‘!:1’ and ‘!$’ refer to the first and last words, respectively, of the same event referenced by the nearest other history reference preceding them on the current command line, or to the previous command if there is no preceding reference.

The character sequence ‘^foo^bar’ (where ‘^’ is actually the second character of the histchars parameter) repeats the last command, replacing the string foo with bar. More precisely, the sequence ‘^foo^bar^’ is synonymous with ‘!!:s^foo^bar^’, hence other modifiers (see the section ‘Modifiers’) may follow the final ‘^’. In particular, ‘^foo^bar^:G’ performs a global substitution.

If the shell encounters the character sequence ‘!"’ in the input, the history mechanism is temporarily disabled until the current list (see zshmisc(1)) is fully parsed. The ‘!"’ is removed from the input, and any subsequent ‘!’ characters have no special significance.

A less convenient but more comprehensible form of command history support is provided by the fc builtin.

    Event Designators

An event designator is a reference to a command-line entry in the history list. In the list below, remember that the initial ‘!’ in each item may be changed to another character by setting the histchars parameter.

! Start a history expansion, except when followed by a blank, newline, ‘=’ or ‘(’. If followed immediately by a word designator (see the section ‘Word Designators’), this forms a history reference with no event designator (see the section ‘Overview’).
!! Refer to the previous command. By itself, this expansion repeats the previous command.
!n Refer to command-line n.
!-n Refer to the current command-line minus n.
!str Refer to the most recent command starting with str.
!?str[?]
  Refer to the most recent command containing str. The trailing ‘?’ is necessary if this reference is to be followed by a modifier or followed by any text that is not to be considered part of str.
!# Refer to the current command line typed in so far. The line is treated as if it were complete up to and including the word before the one with the ‘!#’ reference.
!{...} Insulate a history reference from adjacent characters (if necessary).

    Word Designators

A word designator indicates which word or words of a given command line are to be included in a history reference. A ‘:’ usually separates the event specification from the word designator. It may be omitted only if the word designator begins with a ‘^’, ‘$’, ‘*’, ‘-’ or ‘%’. Word designators include:

0 The first input word (command).
n The nth argument.
^ The first argument. That is, 1.
$ The last argument.
% The word matched by (the most recent) ?str search.
x-y A range of words; x defaults to 0.
* All the arguments, or a null value if there are none.
x* Abbreviates ‘x-$’.
x- Like ‘x*’ but omitting word $.
Note that a ‘%’ word designator works only when used in one of ‘!%’, ‘!:%’ or ‘!?str?:%’, and only when used after a !? expansion (possibly in an earlier command). Anything else results in an error, although the error may not be the most obvious one.

    Modifiers

After the optional word designator, you can add a sequence of one or more of the following modifiers, each preceded by a ‘:’. These modifiers also work on the result of filename generation and parameter expansion, except where noted.

a Turn a file name into an absolute path: prepends the current directory, if necessary, and resolves any use of ‘..’ and ‘.’ in the path. Note that the transformation takes place even if the file or any intervening directories do not exist.
A As ‘a’, but also resolve use of symbolic links where possible. Note that resolution of ‘..’ occurs before resolution of symbolic links. This call is equivalent to a unless your system has the realpath system call (modern systems do).
c Resolve a command name into an absolute path by searching the command path given by the PATH variable. This does not work for commands containing directory parts. Note also that this does not usually work as a glob qualifier unless a file of the same name is found in the current directory.
e Remove all but the part of the filename extension following the ‘.’; see the definition of the filename extension in the description of the r modifier below. Note that according to that definition the result will be empty if the string ends with a ‘.’.
h Remove a trailing pathname component, leaving the head. This works like ‘dirname’.
l Convert the words to all lowercase.
p Print the new command but do not execute it. Only works with history expansion.
q Quote the substituted words, escaping further substitutions. Works with history expansion and parameter expansion, though for parameters it is only useful if the resulting text is to be re-evaluated such as by eval.
Q Remove one level of quotes from the substituted words.
r Remove a filename extension leaving the root name. Strings with no filename extension are not altered. A filename extension is a ‘.’ followed by any number of characters (including zero) that are neither ‘.’ nor ‘/’ and that continue to the end of the string. For example, the extension of ‘foo.orig.c’ is ‘.c’, and ‘dir.c/foo’ has no extension.
s/l/r[/]
  Substitute r for l as described below. The substitution is done only for the first string that matches l. For arrays and for filename generation, this applies to each word of the expanded text. See below for further notes on substitutions.

The forms ‘gs/l/r’ and ‘s/l/r/:G’ perform global substitution, i.e. substitute every occurrence of r for l. Note that the g or :G must appear in exactly the position shown.

See further notes on this form of substitution below.

& Repeat the previous s substitution. Like s, may be preceded immediately by a g. In parameter expansion the & must appear inside braces, and in filename generation it must be quoted with a backslash.
t Remove all leading pathname components, leaving the tail. This works like ‘basename’.
u Convert the words to all uppercase.
x Like q, but break into words at whitespace. Does not work with parameter expansion.
The s/l/r/ substitution works as follows. By default the left-hand side of substitutions are not patterns, but character strings. Any character can be used as the delimiter in place of ‘/’. A backslash quotes the delimiter character. The character ‘&’, in the right-hand-side r, is replaced by the text from the left-hand-side l. The ‘&’ can be quoted with a backslash. A null l uses the previous string either from the previous l or from the contextual scan string s from ‘!?s’. You can omit the rightmost delimiter if a newline immediately follows r; the rightmost ‘?’ in a context scan can similarly be omitted. Note the same record of the last l and r is maintained across all forms of expansion.
Note that if a ‘&’ is used within glob qualifiers an extra backslash is needed as a & is a special character in this case.
Also note that the order of expansions affects the interpretation of l and r. When used in a history expansion, which occurs before any other expansions, l and r are treated as literal strings (except as explained for HIST_SUBST_PATTERN below). When used in parameter expansion, the replacement of r into the parameter’s value is done first, and then any additional process, parameter, command, arithmetic, or brace references are applied, which may evaluate those substitutions and expansions more than once if l appears more than once in the starting value. When used in a glob qualifier, any substitutions or expansions are performed once at the time the qualifier is parsed, even before the ‘:s’ expression itself is divided into l and r sides.
If the option HIST_SUBST_PATTERN is set, l is treated as a pattern of the usual form described in the section FILENAME GENERATION below. This can be used in all the places where modifiers are available; note, however, that in globbing qualifiers parameter substitution has already taken place, so parameters in the replacement string should be quoted to ensure they are replaced at the correct time. Note also that complicated patterns used in globbing qualifiers may need the extended glob qualifier notation (#q:s/.../.../) in order for the shell to recognize the expression as a glob qualifier. Further, note that bad patterns in the substitution are not subject to the NO_BAD_PATTERN option so will cause an error.
When HIST_SUBST_PATTERN is set, l may start with a # to indicate that the pattern must match at the start of the string to be substituted, and a % may appear at the start or after an # to indicate that the pattern must match at the end of the string to be substituted. The % or # may be quoted with two backslashes.
For example, the following piece of filename generation code with the EXTENDED_GLOB option:

 
print *.c(#q:s/#%(#b)s(*).c/’S${match[1]}.C’/)

takes the expansion of *.c and applies the glob qualifiers in the (#q...) expression, which consists of a substitution modifier anchored to the start and end of each word (#%). This turns on backreferences ((#b)), so that the parenthesised subexpression is available in the replacement string as ${match[1]}. The replacement string is quoted so that the parameter is not substituted before the start of filename generation.
The following f, F, w and W modifiers work only with parameter expansion and filename generation. They are listed here to provide a single point of reference for all modifiers.
f Repeats the immediately (without a colon) following modifier until the resulting word doesn’t change any more.
F:expr: Like f, but repeats only n times if the expression expr evaluates to n. Any character can be used instead of the ‘:’; if ‘(’, ‘[’, or ‘{’ is used as the opening delimiter, the closing delimiter should be ’)’, ‘]’, or ‘}’, respectively.
w Makes the immediately following modifier work on each word in the string.
W:sep: Like w but words are considered to be the parts of the string that are separated by sep. Any character can be used instead of the ‘:’; opening parentheses are handled specially, see above.

PROCESS SUBSTITUTION

Each part of a command argument that takes the form ‘<(list)’, ‘>(list)’ or ‘=(list)’ is subject to process substitution. The expression may be preceded or followed by other strings except that, to prevent clashes with commonly occurring strings and patterns, the last form must occur at the start of a command argument, and the forms are only expanded when first parsing command or assignment arguments. Process substitutions may be used following redirection operators; in this case, the substitution must appear with no trailing string.

Note that ‘<<(list)’ is not a special syntax; it is equivalent to ‘< <(list)’, redirecting standard input from the result of process substitution. Hence all the following documentation applies. The second form (with the space) is recommended for clarity.

In the case of the < or > forms, the shell runs the commands in list as a subprocess of the job executing the shell command line. If the system supports the /dev/fd mechanism, the command argument is the name of the device file corresponding to a file descriptor; otherwise, if the system supports named pipes (FIFOs), the command argument will be a named pipe. If the form with > is selected then writing on this special file will provide input for list. If < is used, then the file passed as an argument will be connected to the output of the list process. For example,

paste <(cut -f1 file1) <(cut -f3 file2) |
tee >(process1) >(process2) >/dev/null

cuts fields 1 and 3 from the files file1 and file2 respectively, pastes the results together, and sends it to the processes process1 and process2.

If =(...) is used instead of <(...), then the file passed as an argument will be the name of a temporary file containing the output of the list process. This may be used instead of the < form for a program that expects to lseek (see lseek(2)) on the input file.

There is an optimisation for substitutions of the form =(<<<arg), where arg is a single-word argument to the here-string redirection <<<. This form produces a file name containing the value of arg after any substitutions have been performed. This is handled entirely within the current shell. This is effectively the reverse of the special form $(<arg) which treats arg as a file name and replaces it with the file’s contents.

The = form is useful as both the /dev/fd and the named pipe implementation of <(...) have drawbacks. In the former case, some programmes may automatically close the file descriptor in question before examining the file on the command line, particularly if this is necessary for security reasons such as when the programme is running setuid. In the second case, if the programme does not actually open the file, the subshell attempting to read from or write to the pipe will (in a typical implementation, different operating systems may have different behaviour) block for ever and have to be killed explicitly. In both cases, the shell actually supplies the information using a pipe, so that programmes that expect to lseek (see lseek(2)) on the file will not work.

Also note that the previous example can be more compactly and efficiently written (provided the MULTIOS option is set) as:

paste <(cut -f1 file1) <(cut -f3 file2) \
> >(process1) > >(process2)

The shell uses pipes instead of FIFOs to implement the latter two process substitutions in the above example.

There is an additional problem with >(process); when this is attached to an external command, the parent shell does not wait for process to finish and hence an immediately following command cannot rely on the results being complete. The problem and solution are the same as described in the section MULTIOS in zshmisc(1). Hence in a simplified version of the example above:

paste <(cut -f1 file1) <(cut -f3 file2) > >(process)

(note that no MULTIOS are involved), process will be run asynchronously as far as the parent shell is concerned. The workaround is:

{ paste <(cut -f1 file1) <(cut -f3 file2) } > >(process)

The extra processes here are spawned from the parent shell which will wait for their completion.

Another problem arises any time a job with a substitution that requires a temporary file is disowned by the shell, including the case where ‘&!’ or ‘&|’ appears at the end of a command containing a substitution. In that case the temporary file will not be cleaned up as the shell no longer has any memory of the job. A workaround is to use a subshell, for example,

(mycmd =(myoutput)) &!

as the forked subshell will wait for the command to finish then remove the temporary file.

A general workaround to ensure a process substitution endures for an appropriate length of time is to pass it as a parameter to an anonymous shell function (a piece of shell code that is run immediately with function scope). For example, this code:

() {
   print File $1:
   cat $1
} =(print This be the verse)

outputs something resembling the following

File /tmp/zsh6nU0kS:
This be the verse

The temporary file created by the process substitution will be deleted when the function exits.

PARAMETER EXPANSION

The character ‘$’ is used to introduce parameter expansions. See zshparam(1) for a description of parameters, including arrays, associative arrays, and subscript notation to access individual array elements.

Note in particular the fact that words of unquoted parameters are not automatically split on whitespace unless the option SH_WORD_SPLIT is set; see references to this option below for more details. This is an important difference from other shells.

In the expansions discussed below that require a pattern, the form of the pattern is the same as that used for filename generation; see the section ‘Filename Generation’. Note that these patterns, along with the replacement text of any substitutions, are themselves subject to parameter expansion, command substitution, and arithmetic expansion. In addition to the following operations, the colon modifiers described in the section ‘Modifiers’ in the section ‘History Expansion’ can be applied: for example, ${i:s/foo/bar/} performs string substitution on the expansion of parameter $i.

${name}
  The value, if any, of the parameter name is substituted. The braces are required if the expansion is to be followed by a letter, digit, or underscore that is not to be interpreted as part of name. In addition, more complicated forms of substitution usually require the braces to be present; exceptions, which only apply if the option KSH_ARRAYS is not set, are a single subscript or any colon modifiers appearing after the name, or any of the characters ‘^’, ‘=’, ‘~’, ‘#’ or ‘+’ appearing before the name, all of which work with or without braces.

If name is an array parameter, and the KSH_ARRAYS option is not set, then the value of each element of name is substituted, one element per word. Otherwise, the expansion results in one word only; with KSH_ARRAYS, this is the first element of an array. No field splitting is done on the result unless the SH_WORD_SPLIT option is set. See also the flags = and s:string:.

${+name}
  If name is the name of a set parameter ‘1’ is substituted, otherwise ‘0’ is substituted.
${name-word}
${name:-word}
  If name is set, or in the second form is non-null, then substitute its value; otherwise substitute word. In the second form name may be omitted, in which case word is always substituted.
${name+word}
${name:+word}
  If name is set, or in the second form is non-null, then substitute word; otherwise substitute nothing.
${name=word}
${name:=word}
${name::=word}
  In the first form, if name is unset then set it to word; in the second form, if name is unset or null then set it to word; and in the third form, unconditionally set name to word. In all forms, the value of the parameter is then substituted.
${name?word}
${name:?word}
  In the first form, if name is set, or in the second form if name is both set and non-null, then substitute its value; otherwise, print word and exit from the shell. Interactive shells instead return to the prompt. If word is omitted, then a standard message is printed.
In any of the above expressions that test a variable and substitute an alternate word, note that you can use standard shell quoting in the word value to selectively override the splitting done by the SH_WORD_SPLIT option and the = flag, but not splitting by the s:string: flag.
In the following expressions, when name is an array and the substitution is not quoted, or if the ‘(@)’ flag or the name[@] syntax is used, matching and replacement is performed on each array element separately.
${name#pattern}
${name##pattern}
  If the pattern matches the beginning of the value of name, then substitute the value of name with the matched portion deleted; otherwise, just substitute the value of name. In the first form, the smallest matching pattern is preferred; in the second form, the largest matching pattern is preferred.
${name%pattern}
${name%%pattern}
  If the pattern matches the end of the value of name, then substitute the value of name with the matched portion deleted; otherwise, just substitute the value of name. In the first form, the smallest matching pattern is preferred; in the second form, the largest matching pattern is preferred.
${name:#pattern}
  If the pattern matches the value of name, then substitute the empty string; otherwise, just substitute the value of name. If name is an array the matching array elements are removed (use the ‘(M)’ flag to remove the non-matched elements).
${name:|arrayname}
  If arrayname is the name (N.B., not contents) of an array variable, then any elements contained in arrayname are removed from the substitution of name. If the substitution is scalar, either because name is a scalar variable or the expression is quoted, the elements of arrayname are instead tested against the entire expression.
${name:*arrayname}
  Similar to the preceding substitution, but in the opposite sense, so that entries present in both the original substitution and as elements of arrayname are retained and others removed.
${name:^arrayname}
${name:^^arrayname}
  Zips two arrays, such that the output array is twice as long as the shortest (longest for ‘:^^’) of name and arrayname, with the elements alternatingly being picked from them. For ‘:^’, if one of the input arrays is longer, the output will stop when the end of the shorter array is reached. Thus,

 
a=(1 2 3 4); b=(a b); print ${a:^b}

will output ‘1 a 2 b’. For ‘:^^’, then the input is repeated until all of the longer array has been used up and the above will output ‘1 a 2 b 3 a 4 b’.

Either or both inputs may be a scalar, they will be treated as an array of length 1 with the scalar as the only element. If either array is empty, the other array is output with no extra elements inserted.

Currently the following code will output ‘a b’ and ‘1’ as two separate elements, which can be unexpected. The second print provides a workaround which should continue to work if this is changed.

 
a=(a b); b=(1 2); print -l "${a:^b}"; print -l "${${a:^b}}"

${name:offset}
${name:offset:length}
  This syntax gives effects similar to parameter subscripting in the form $name[start,end], but is compatible with other shells; note that both offset and length are interpreted differently from the components of a subscript.

If offset is non-negative, then if the variable name is a scalar substitute the contents starting offset characters from the first character of the string, and if name is an array substitute elements starting offset elements from the first element. If length is given, substitute that many characters or elements, otherwise the entire rest of the scalar or array.

A positive offset is always treated as the offset of a character or element in name from the first character or element of the array (this is different from native zsh subscript notation). Hence 0 refers to the first character or element regardless of the setting of the option KSH_ARRAYS.

A negative offset counts backwards from the end of the scalar or array, so that -1 corresponds to the last character or element, and so on.

When positive, length counts from the offset position toward the end of the scalar or array. When negative, length counts back from the end. If this results in a position smaller than offset, a diagnostic is printed and nothing is substituted.

The option MULTIBYTE is obeyed, i.e. the offset and length count multibyte characters where appropriate.

offset and length undergo the same set of shell substitutions as for scalar assignment; in addition, they are then subject to arithmetic evaluation. Hence, for example

 
print ${foo:3}
print ${foo: 1 + 2}
print ${foo:$(( 1 + 2))}
print ${foo:$(echo 1 + 2)}

all have the same effect, extracting the string starting at the fourth character of $foo if the substitution would otherwise return a scalar, or the array starting at the fourth element if $foo would return an array. Note that with the option KSH_ARRAYS $foo always returns a scalar (regardless of the use of the offset syntax) and a form such as $foo[*]:3 is required to extract elements of an array named foo.

If offset is negative, the - may not appear immediately after the : as this indicates the ${name:-word} form of substitution. Instead, a space may be inserted before the -. Furthermore, neither offset nor length may begin with an alphabetic character or & as these are used to indicate history-style modifiers. To substitute a value from a variable, the recommended approach is to precede it with a $ as this signifies the intention (parameter substitution can easily be rendered unreadable); however, as arithmetic substitution is performed, the expression ${var: offs} does work, retrieving the offset from $offs.

For further compatibility with other shells there is a special case for array offset 0. This usually accesses to the first element of the array. However, if the substitution refers the positional parameter array, e.g. $@ or $*, then offset 0 instead refers to $0, offset 1 refers to $1, and so on. In other words, the positional parameter array is effectively extended by prepending $0. Hence ${*:0:1} substitutes $0 and ${*:1:1} substitutes $1.

${name/pattern/repl}
${name//pattern/repl}
  Replace the longest possible match of pattern in the expansion of parameter name by string repl. The first form replaces just the first occurrence, the second form all occurrences. Both pattern and repl are subject to double-quoted substitution, so that expressions like ${name/$opat/$npat} will work, but note the usual rule that pattern characters in $opat are not treated specially unless either the option GLOB_SUBST is set, or $opat is instead substituted as ${~opat}.

The pattern may begin with a ‘#’, in which case the pattern must match at the start of the string, or ‘%’, in which case it must match at the end of the string, or ‘#%’ in which case the pattern must match the entire string. The repl may be an empty string, in which case the final ‘/’ may also be omitted. To quote the final ‘/’ in other cases it should be preceded by a single backslash; this is not necessary if the ‘/’ occurs inside a substituted parameter. Note also that the ‘#’, ‘%’ and ‘#% are not active if they occur inside a substituted parameter, even at the start.

The first ‘/’ may be preceded by a ‘:’, in which case the match will only succeed if it matches the entire word. Note also the effect of the I and S parameter expansion flags below; however, the flags M, R, B, E and N are not useful.

For example,

 
foo="twinkle twinkle little star" sub="t*e" rep="spy"
print ${foo//${~sub}/$rep}
print ${(S)foo//${~sub}/$rep}

Here, the ‘~’ ensures that the text of $sub is treated as a pattern rather than a plain string. In the first case, the longest match for t*e is substituted and the result is ‘spy star’, while in the second case, the shortest matches are taken and the result is ‘spy spy lispy star’.

${#spec}
  If spec is one of the above substitutions, substitute the length in characters of the result instead of the result itself. If spec is an array expression, substitute the number of elements of the result. This has the side-effect that joining is skipped even in quoted forms, which may affect other sub-expressions in spec. Note that ‘^’, ‘=’, and ‘~’, below, must appear to the left of ‘#’ when these forms are combined.

If the option POSIX_IDENTIFIERS is not set, and spec is a simple name, then the braces are optional; this is true even for special parameters so e.g. $#- and $#* take the length of the string $- and the array $* respectively. If POSIX_IDENTIFIERS is set, then braces are required for the # to be treated in this fashion.

${^spec}
  Turn on the RC_EXPAND_PARAM option for the evaluation of spec; if the ‘^’ is doubled, turn it off. When this option is set, array expansions of the form foo${xx}bar, where the parameter xx is set to (a b c), are substituted with ‘fooabar foobbar foocbar’ instead of the default ‘fooa b cbar’. Note that an empty array will therefore cause all arguments to be removed.

Internally, each such expansion is converted into the equivalent list for brace expansion. E.g., ${^var} becomes {$var[1],$var[2],...}, and is processed as described in the section ‘Brace Expansion’ below. If word splitting is also in effect the $var[N] may themselves be split into different list elements.

${=spec}
  Perform word splitting using the rules for SH_WORD_SPLIT during the evaluation of spec, but regardless of whether the parameter appears in double quotes; if the ‘=’ is doubled, turn it off. This forces parameter expansions to be split into separate words before substitution, using IFS as a delimiter. This is done by default in most other shells.

Note that splitting is applied to word in the assignment forms of spec before the assignment to name is performed. This affects the result of array assignments with the A flag.

${~spec}
  Turn on the GLOB_SUBST option for the evaluation of spec; if the ‘~’ is doubled, turn it off. When this option is set, the string resulting from the expansion will be interpreted as a pattern anywhere that is possible, such as in filename expansion and filename generation and pattern-matching contexts like the right hand side of the ‘=’ and ‘!=’ operators in conditions.

In nested substitutions, note that the effect of the ~ applies to the result of the current level of substitution. A surrounding pattern operation on the result may cancel it. Hence, for example, if the parameter foo is set to *, ${~foo//\*/*.c} is substituted by the pattern *.c, which may be expanded by filename generation, but ${${~foo}//\*/*.c} substitutes to the string *.c, which will not be further expanded.

If a ${...} type parameter expression or a $(...) type command substitution is used in place of name above, it is expanded first and the result is used as if it were the value of name. Thus it is possible to perform nested operations: ${${foo#head}%tail} substitutes the value of $foo with both ‘head’ and ‘tail’ deleted. The form with $(...) is often useful in combination with the flags described next; see the examples below. Each name or nested ${...} in a parameter expansion may also be followed by a subscript expression as described in Array Parameters in zshparam(1).

Note that double quotes may appear around nested expressions, in which case only the part inside is treated as quoted; for example, ${(f)"$(foo)"} quotes the result of $(foo), but the flag ‘(f)’ (see below) is applied using the rules for unquoted expansions. Note further that quotes are themselves nested in this context; for example, in "${(@f)"$(foo)"}", there are two sets of quotes, one surrounding the whole expression, the other (redundant) surrounding the $(foo) as before.

    Parameter Expansion Flags

If the opening brace is directly followed by an opening parenthesis, the string up to the matching closing parenthesis will be taken as a list of flags. In cases where repeating a flag is meaningful, the repetitions need not be consecutive; for example, ‘(q%q%q)’ means the same thing as the more readable ‘(%%qqq)’. The following flags are supported:

# Evaluate the resulting words as numeric expressions and output the characters corresponding to the resulting integer. Note that this form is entirely distinct from use of the # without parentheses.

If the MULTIBYTE option is set and the number is greater than 127 (i.e. not an ASCII character) it is treated as a Unicode character.

% Expand all % escapes in the resulting words in the same way as in prompts (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)). If this flag is given twice, full prompt expansion is done on the resulting words, depending on the setting of the PROMPT_PERCENT, PROMPT_SUBST and PROMPT_BANG options.
@ In double quotes, array elements are put into separate words. E.g., ‘"${(@)foo}"’ is equivalent to ‘"${foo[@]}"’ and ‘"${(@)foo[1,2]}"’ is the same as ‘"$foo[1]" "$foo[2]"’. This is distinct from field splitting by the f, s or z flags, which still applies within each array element.
A Create an array parameter with ‘${...=...}’, ‘${...:=...}’ or ‘${...::=...}’. If this flag is repeated (as in ‘AA’), create an associative array parameter. Assignment is made before sorting or padding; if field splitting is active, the word part is split before assignment. The name part may be a subscripted range for ordinary arrays; the word part must be converted to an array, for example by using ‘${(AA)=name=...}’ to activate field splitting, when creating an associative array.
a Sort in array index order; when combined with ‘O’ sort in reverse array index order. Note that ‘a’ is therefore equivalent to the default but ‘Oa’ is useful for obtaining an array’s elements in reverse order.
b Quote with backslashes only characters that are special to pattern matching. This is useful when the contents of the variable are to be tested using GLOB_SUBST, including the ${~...} switch.

Quoting using one of the q family of flags does not work for this purpose since quotes are not stripped from non-pattern characters by GLOB_SUBST. In other words,

 
pattern=${(q)str}
[[ $str = ${~pattern} ]]

works if $str is ‘a*b’ but not if it is ‘a b’, whereas

 
pattern=${(b)str}
[[ $str = ${~pattern} ]]

is always true for any possible value of $str.

c With ${#name}, count the total number of characters in an array, as if the elements were concatenated with spaces between them. This is not a true join of the array, so other expressions used with this flag may have an effect on the elements of the array before it is counted.
C Capitalize the resulting words. ‘Words’ in this case refers to sequences of alphanumeric characters separated by non-alphanumerics, not to words that result from field splitting.
D Assume the string or array elements contain directories and attempt to substitute the leading part of these by names. The remainder of the path (the whole of it if the leading part was not substituted) is then quoted so that the whole string can be used as a shell argument. This is the reverse of ‘~’ substitution: see the section FILENAME EXPANSION below.
e Perform parameter expansion, command substitution and arithmetic expansion on the result. Such expansions can be nested but too deep recursion may have unpredictable effects.
f Split the result of the expansion at newlines. This is a shorthand for ‘ps:\n:’.
F Join the words of arrays together using newline as a separator. This is a shorthand for ‘pj:\n:’.
g:opts: Process escape sequences like the echo builtin when no options are given (g::). With the o option, octal escapes don’t take a leading zero. With the c option, sequences like ‘^X’ are also processed. With the e option, processes ‘\M-t’ and similar sequences like the print builtin. With both of the o and e options, behaves like the print builtin except that in none of these modes is ‘\c’ interpreted.
i Sort case-insensitively. May be combined with ‘n’ or ‘O’.
k If name refers to an associative array, substitute the keys (element names) rather than the values of the elements. Used with subscripts (including ordinary arrays), force indices or keys to be substituted even if the subscript form refers to values. However, this flag may not be combined with subscript ranges.
L Convert all letters in the result to lower case.
n Sort decimal integers numerically; if the first differing characters of two test strings are not digits, sorting is lexical. Integers with more initial zeroes are sorted before those with fewer or none. Hence the array ‘foo1 foo02 foo2 foo3 foo20 foo23’ is sorted into the order shown. May be combined with ‘i’ or ‘O’.
o Sort the resulting words in ascending order; if this appears on its own the sorting is lexical and case-sensitive (unless the locale renders it case-insensitive). Sorting in ascending order is the default for other forms of sorting, so this is ignored if combined with ‘a’, ‘i’ or ‘n’.
O Sort the resulting words in descending order; ‘O’ without ‘a’, ‘i’ or ‘n’ sorts in reverse lexical order. May be combined with ‘a’, ‘i’ or ‘n’ to reverse the order of sorting.
P This forces the value of the parameter name to be interpreted as a further parameter name, whose value will be used where appropriate. Note that flags set with one of the typeset family of commands (in particular case transformations) are not applied to the value of name used in this fashion.

If used with a nested parameter or command substitution, the result of that will be taken as a parameter name in the same way. For example, if you have ‘foo=bar’ and ‘bar=baz’, the strings ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be expanded to ‘baz’.

Likewise, if the reference is itself nested, the expression with the flag is treated as if it were directly replaced by the parameter name. It is an error if this nested substitution produces an array with more than one word. For example, if ‘name=assoc’ where the parameter assoc is an associative array, then ‘${${(P)name}[elt]}’ refers to the element of the associative subscripted ‘elt’.

q Quote characters that are special to the shell in the resulting words with backslashes; unprintable or invalid characters are quoted using the $’\NNN form, with separate quotes for each octet.

If this flag is given twice, the resulting words are quoted in single quotes and if it is given three times, the words are quoted in double quotes; in these forms no special handling of unprintable or invalid characters is attempted. If the flag is given four times, the words are quoted in single quotes preceded by a $. Note that in all three of these forms quoting is done unconditionally, even if this does not change the way the resulting string would be interpreted by the shell.

If a q- is given (only a single q may appear), a minimal form of single quoting is used that only quotes the string if needed to protect special characters. Typically this form gives the most readable output.

Q Remove one level of quotes from the resulting words.
t Use a string describing the type of the parameter where the value of the parameter would usually appear. This string consists of keywords separated by hyphens (‘-’). The first keyword in the string describes the main type, it can be one of ‘scalar’, ‘array’, ‘integer’, ‘float’ or ‘association’. The other keywords describe the type in more detail:

local for local parameters
left for left justified parameters
right_blanks
  for right justified parameters with leading blanks
right_zeros
  for right justified parameters with leading zeros
lower for parameters whose value is converted to all lower case when it is expanded
upper for parameters whose value is converted to all upper case when it is expanded
readonly
  for readonly parameters
tag for tagged parameters
export for exported parameters
unique for arrays which keep only the first occurrence of duplicated values
hide for parameters with the ‘hide’ flag
hideval
  for parameters with the ‘hideval’ flag
special
  for special parameters defined by the shell

u Expand only the first occurrence of each unique word.
U Convert all letters in the result to upper case.
v Used with k, substitute (as two consecutive words) both the key and the value of each associative array element. Used with subscripts, force values to be substituted even if the subscript form refers to indices or keys.
V Make any special characters in the resulting words visible.
w With ${#name}, count words in arrays or strings; the s flag may be used to set a word delimiter.
W Similar to w with the difference that empty words between repeated delimiters are also counted.
X With this flag, parsing errors occurring with the Q, e and # flags or the pattern matching forms such as ‘${name#pattern}’ are reported. Without the flag, errors are silently ignored.
z Split the result of the expansion into words using shell parsing to find the words, i.e. taking into account any quoting in the value. Comments are not treated specially but as ordinary strings, similar to interactive shells with the INTERACTIVE_COMMENTS option unset (however, see the Z flag below for related options)

Note that this is done very late, even later than the ‘(s)’ flag. So to access single words in the result use nested expansions as in ‘${${(z)foo}[2]}’. Likewise, to remove the quotes in the resulting words use ‘${(Q)${(z)foo}}’.

0 Split the result of the expansion on null bytes. This is a shorthand for ‘ps:\0:’.
The following flags (except p) are followed by one or more arguments as shown. Any character, or the matching pairs ‘(...)’, ‘{...}’, ‘[...]’, or ‘<...>’, may be used in place of a colon as delimiters, but note that when a flag takes more than one argument, a matched pair of delimiters must surround each argument.
p Recognize the same escape sequences as the print builtin in string arguments to any of the flags described below that follow this argument.

Alternatively, with this option string arguments may be in the form $var in which case the value of the variable is substituted. Note this form is strict; the string argument does not undergo general parameter expansion.

For example,

 
sep=:
val=a:b:c
print ${(ps.$sep.)val}

splits the variable on a :.

~ Strings inserted into the expansion by any of the flags below are to be treated as patterns. This applies to the string arguments of flags that follow ~ within the same set of parentheses. Compare with ~ outside parentheses, which forces the entire substituted string to be treated as a pattern. Hence, for example,

 
[[ "?" = ${(~j.|.)array} ]]

treats ‘|’ as a pattern and succeeds if and only if $array contains the string ‘?’ as an element. The ~ may be repeated to toggle the behaviour; its effect only lasts to the end of the parenthesised group.

j:string:
  Join the words of arrays together using string as a separator. Note that this occurs before field splitting by the s:string: flag or the SH_WORD_SPLIT option.
l:expr::string1::string2:
  Pad the resulting words on the left. Each word will be truncated if required and placed in a field expr characters wide.

The arguments :string1: and :string2: are optional; neither, the first, or both may be given. Note that the same pairs of delimiters must be used for each of the three arguments. The space to the left will be filled with string1 (concatenated as often as needed) or spaces if string1 is not given. If both string1 and string2 are given, string2 is inserted once directly to the left of each word, truncated if necessary, before string1 is used to produce any remaining padding.

If either of string1 or string2 is present but empty, i.e. there are two delimiters together at that point, the first character of $IFS is used instead.

If the MULTIBYTE option is in effect, the flag m may also be given, in which case widths will be used for the calculation of padding; otherwise individual multibyte characters are treated as occupying one unit of width.

If the MULTIBYTE option is not in effect, each byte in the string is treated as occupying one unit of width.

Control characters are always assumed to be one unit wide; this allows the mechanism to be used for generating repetitions of control characters.

m Only useful together with one of the flags l or r or with the # length operator when the MULTIBYTE option is in effect. Use the character width reported by the system in calculating how much of the string it occupies or the overall length of the string. Most printable characters have a width of one unit, however certain Asian character sets and certain special effects use wider characters; combining characters have zero width. Non-printable characters are arbitrarily counted as zero width; how they would actually be displayed will vary.

If the m is repeated, the character either counts zero (if it has zero width), else one. For printable character strings this has the effect of counting the number of glyphs (visibly separate characters), except for the case where combining characters themselves have non-zero width (true in certain alphabets).

r:expr::string1::string2:
  As l, but pad the words on the right and insert string2 immediately to the right of the string to be padded.

Left and right padding may be used together. In this case the strategy is to apply left padding to the first half width of each of the resulting words, and right padding to the second half. If the string to be padded has odd width the extra padding is applied on the left.

s:string:
  Force field splitting at the separator string. Note that a string of two or more characters means that all of them must match in sequence; this differs from the treatment of two or more characters in the IFS parameter. See also the = flag and the SH_WORD_SPLIT option. An empty string may also be given in which case every character will be a separate element.

For historical reasons, the usual behaviour that empty array elements are retained inside double quotes is disabled for arrays generated by splitting; hence the following:

 
line="one::three"
print -l "${(s.:.)line}"

produces two lines of output for one and three and elides the empty field. To override this behaviour, supply the ‘(@)’ flag as well, i.e. "${(@s.:.)line}".

Z:opts: As z but takes a combination of option letters between a following pair of delimiter characters. With no options the effect is identical to z. (Z+c+) causes comments to be parsed as a string and retained; any field in the resulting array beginning with an unquoted comment character is a comment. (Z+C+) causes comments to be parsed and removed. The rule for comments is standard: anything between a word starting with the third character of $HISTCHARS, default #, up to the next newline is a comment. (Z+n+) causes unquoted newlines to be treated as ordinary whitespace, else they are treated as if they are shell code delimiters and converted to semicolons. Options are combined within the same set of delimiters, e.g. (Z+Cn+).
_:flags:
  The underscore (_) flag is reserved for future use. As of this revision of zsh, there are no valid flags; anything following an underscore, other than an empty pair of delimiters, is treated as an error, and the flag itself has no effect.
The following flags are meaningful with the ${...#...} or ${...%...} forms. The S and I flags may also be used with the ${.../...} forms.
S Search substrings as well as beginnings or ends; with # start from the beginning and with % start from the end of the string. With substitution via ${.../...} or ${...//...}, specifies non-greedy matching, i.e. that the shortest instead of the longest match should be replaced.
I:expr: Search the exprth match (where expr evaluates to a number). This only applies when searching for substrings, either with the S flag, or with ${.../...} (only the exprth match is substituted) or ${...//...} (all matches from the exprth on are substituted). The default is to take the first match.

The exprth match is counted such that there is either one or zero matches from each starting position in the string, although for global substitution matches overlapping previous replacements are ignored. With the ${...%...} and ${...%%...} forms, the starting position for the match moves backwards from the end as the index increases, while with the other forms it moves forward from the start.

Hence with the string
 
which switch is the right switch for Ipswich?

substitutions of the form ${(SI:N:)string#w*ch} as N increases from 1 will match and remove ‘which’, ‘witch’, ‘witch’ and ‘wich’; the form using ‘##’ will match and remove ‘which switch is the right switch for Ipswich’, ‘witch is the right switch for Ipswich’, ‘witch for Ipswich’ and ‘wich’. The form using ‘%’ will remove the same matches as for ‘#’, but in reverse order, and the form using ‘%%’ will remove the same matches as for ‘##’ in reverse order.

B Include the index of the beginning of the match in the result.
E Include the index of the end of the match in the result.
M Include the matched portion in the result.
N Include the length of the match in the result.
R Include the unmatched portion in the result (the Rest).

    Rules

Here is a summary of the rules for substitution; this assumes that braces are present around the substitution, i.e. ${...}. Some particular examples are given below. Note that the Zsh Development Group accepts no responsibility for any brain damage which may occur during the reading of the following rules.

1. Nested substitution
  If multiple nested ${...} forms are present, substitution is performed from the inside outwards. At each level, the substitution takes account of whether the current value is a scalar or an array, whether the whole substitution is in double quotes, and what flags are supplied to the current level of substitution, just as if the nested substitution were the outermost. The flags are not propagated up to enclosing substitutions; the nested substitution will return either a scalar or an array as determined by the flags, possibly adjusted for quoting. All the following steps take place where applicable at all levels of substitution.

Note that, unless the ‘(P)’ flag is present, the flags and any subscripts apply directly to the value of the nested substitution; for example, the expansion ${${foo}} behaves exactly the same as ${foo}. When the ‘(P)’ flag is present in a nested substitution, the other substitution rules are applied to the value before it is interpreted as a name, so ${${(P)foo}} may differ from ${(P)foo}.

At each nested level of substitution, the substituted words undergo all forms of single-word substitution (i.e. not filename generation), including command substitution, arithmetic expansion and filename expansion (i.e. leading ~ and =). Thus, for example, ${${:-=cat}:h} expands to the directory where the cat program resides. (Explanation: the internal substitution has no parameter but a default value =cat, which is expanded by filename expansion to a full path; the outer substitution then applies the modifier :h and takes the directory part of the path.)

2. Internal parameter flags
  Any parameter flags set by one of the typeset family of commands, in particular the -L, -R, -Z, -u and -l options for padding and capitalization, are applied directly to the parameter value. Note these flags are options to the command, e.g. ‘typeset -Z’; they are not the same as the flags used within parameter substitutions.

At the outermost level of substitution, the ‘(P)’ flag (rule 4.) ignores these transformations and uses the unmodified value of the parameter as the name to be replaced. This is usually the desired behavior because padding may make the value syntactically illegal as a parameter name, but if capitalization changes are desired, use the ${${(P)foo}} form (rule 25.).

3. Parameter subscripting
  If the value is a raw parameter reference with a subscript, such as ${var[3]}, the effect of subscripting is applied directly to the parameter. Subscripts are evaluated left to right; subsequent subscripts apply to the scalar or array value yielded by the previous subscript. Thus if var is an array, ${var[1][2]} is the second character of the first word, but ${var[2,4][2]} is the entire third word (the second word of the range of words two through four of the original array). Any number of subscripts may appear. Flags such as ‘(k)’ and ‘(v)’ which alter the result of subscripting are applied.
4. Parameter name replacement
  At the outermost level of nesting only, the ‘(P)’ flag is applied. This treats the value so far as a parameter name (which may include a subscript expression) and replaces that with the corresponding value. This replacement occurs later if the ‘(P)’ flag appears in a nested substitution.

If the value so far names a parameter that has internal flags (rule 2.), those internal flags are applied to the new value after replacement.

5. Double-quoted joining
  If the value after this process is an array, and the substitution appears in double quotes, and neither an ‘(@)’ flag nor a ‘#’ length operator is present at the current level, then words of the value are joined with the first character of the parameter $IFS, by default a space, between each word (single word arrays are not modified). If the ‘(j)’ flag is present, that is used for joining instead of $IFS.
6. Nested subscripting
  Any remaining subscripts (i.e. of a nested substitution) are evaluated at this point, based on whether the value is an array or a scalar. As with 3., multiple subscripts can appear. Note that ${foo[2,4][2]} is thus equivalent to ${${foo[2,4]}[2]} and also to "${${(@)foo[2,4]}[2]}" (the nested substitution returns an array in both cases), but not to "${${foo[2,4]}[2]}" (the nested substitution returns a scalar because of the quotes).
7. Modifiers
  Any modifiers, as specified by a trailing ‘#’, ‘%’, ‘/’ (possibly doubled) or by a set of modifiers of the form ‘:...’ (see the section ‘Modifiers’ in the section ‘History Expansion’), are applied to the words of the value at this level.
8. Character evaluation
  Any ‘(#)’ flag is applied, evaluating the result so far numerically as a character.
9. Length
  Any initial ‘#’ modifier, i.e. in the form ${#var}, is used to evaluate the length of the expression so far.
10. Forced joining
  If the ‘(j)’ flag is present, or no ‘(j)’ flag is present but the string is to be split as given by rule 11., and joining did not take place at rule 5., any words in the value are joined together using the given string or the first character of $IFS if none. Note that the ‘(F)’ flag implicitly supplies a string for joining in this manner.
11. Simple word splitting
  If one of the ‘(s)’ or ‘(f)’ flags are present, or the ‘=’ specifier was present (e.g. ${=var}), the word is split on occurrences of the specified string, or (for = with neither of the two flags present) any of the characters in $IFS.

If no ‘(s)’, ‘(f)’ or ‘=’ was given, but the word is not quoted and the option SH_WORD_SPLIT is set, the word is split on occurrences of any of the characters in $IFS. Note this step, too, takes place at all levels of a nested substitution.

12. Case modification
  Any case modification from one of the flags ‘(L)’, ‘(U)’ or ‘(C)’ is applied.
13. Escape sequence replacement
  First any replacements from the ‘(g)’ flag are performed, then any prompt-style formatting from the ‘(%)’ family of flags is applied.
14. Quote application
  Any quoting or unquoting using ‘(q)’ and ‘(Q)’ and related flags is applied.
15. Directory naming
  Any directory name substitution using ‘(D)’ flag is applied.
16. Visibility enhancement
  Any modifications to make characters visible using the ‘(V)’ flag are applied.
17. Lexical word splitting
  If the ’(z)’ flag or one of the forms of the ’(Z)’ flag is present, the word is split as if it were a shell command line, so that quotation marks and other metacharacters are used to decide what constitutes a word. Note this form of splitting is entirely distinct from that described by rule 11.: it does not use $IFS, and does not cause forced joining.
18. Uniqueness
  If the result is an array and the ‘(u)’ flag was present, duplicate elements are removed from the array.
19. Ordering
  If the result is still an array and one of the ‘(o)’ or ‘(O)’ flags was present, the array is reordered.
20. RC_EXPAND_PARAM
  At this point the decision is made whether any resulting array elements are to be combined element by element with surrounding text, as given by either the RC_EXPAND_PARAM option or the ‘^’ flag.
21. Re-evaluation
  Any ‘(e)’ flag is applied to the value, forcing it to be re-examined for new parameter substitutions, but also for command and arithmetic substitutions.
22. Padding
  Any padding of the value by the ‘(l.fill.)’ or ‘(r.fill.)’ flags is applied.
23. Semantic joining
  In contexts where expansion semantics requires a single word to result, all words are rejoined with the first character of IFS between. So in ‘${(P)${(f)lines}}’ the value of ${lines} is split at newlines, but then must be joined again before the ‘(P)’ flag can be applied.

If a single word is not required, this rule is skipped.

24. Empty argument removal
  If the substitution does not appear in double quotes, any resulting zero-length argument, whether from a scalar or an element of an array, is elided from the list of arguments inserted into the command line.

Strictly speaking, the removal happens later as the same happens with other forms of substitution; the point to note here is simply that it occurs after any of the above parameter operations.

25. Nested parameter name replacement
  If the ‘(P)’ flag is present and rule 4. has not applied, the value so far is treated as a parameter name (which may include a subscript expression) and replaced with the corresponding value, with internal flags (rule 2.) applied to the new value.

    Examples

The flag f is useful to split a double-quoted substitution line by line. For example, ${(f)"$(<file)"} substitutes the contents of file divided so that each line is an element of the resulting array. Compare this with the effect of $(<file) alone, which divides the file up by words, or the same inside double quotes, which makes the entire content of the file a single string.

The following illustrates the rules for nested parameter expansions. Suppose that $foo contains the array (bar baz):

"${(@)${foo}[1]}"
  This produces the result b. First, the inner substitution "${foo}", which has no array (@) flag, produces a single word result "bar baz". The outer substitution "${(@)...[1]}" detects that this is a scalar, so that (despite the ‘(@)’ flag) the subscript picks the first character.
"${${(@)foo}[1]}"
  This produces the result ‘bar’. In this case, the inner substitution "${(@)foo}" produces the array ‘(bar baz)’. The outer substitution "${...[1]}" detects that this is an array and picks the first word. This is similar to the simple case "${foo[1]}".
As an example of the rules for word splitting and joining, suppose $foo contains the array ‘(ax1 bx1)’. Then
${(s/x/)foo}
  produces the words ‘a’, ‘1 b’ and ‘1’.
${(j/x/s/x/)foo}
  produces ‘a’, ‘1’, ‘b’ and ‘1’.
${(s/x/)foo%%1*}
  produces ‘a’ and ‘ b’ (note the extra space). As substitution occurs before either joining or splitting, the operation first generates the modified array (ax bx), which is joined to give "ax bx", and then split to give ‘a’, ‘ b’ and ‘’. The final empty string will then be elided, as it is not in double quotes.

COMMAND SUBSTITUTION

A command enclosed in parentheses preceded by a dollar sign, like ‘$(...)’, or quoted with grave accents, like ‘...’, is replaced with its standard output, with any trailing newlines deleted. If the substitution is not enclosed in double quotes, the output is broken into words using the IFS parameter. The substitution ‘$(cat foo)’ may be replaced by the equivalent but faster ‘$(<foo)’. In either case, if the option GLOB_SUBST is set, the output is eligible for filename generation.

ARITHMETIC EXPANSION

A string of the form ‘$[exp]’ or ‘$((exp))’ is substituted with the value of the arithmetic expression exp. exp is subjected to parameter expansion, command substitution and arithmetic expansion before it is evaluated. See the section ‘Arithmetic Evaluation’.

BRACE EXPANSION

A string of the form ‘foo{xx,yy,zz}bar’ is expanded to the individual words ‘fooxxbar’, ‘fooyybar’ and ‘foozzbar’. Left-to-right order is preserved. This construct may be nested. Commas may be quoted in order to include them literally in a word.

An expression of the form ‘{n1..n2}’, where n1 and n2 are integers, is expanded to every number between n1 and n2 inclusive. If either number begins with a zero, all the resulting numbers will be padded with leading zeroes to that minimum width, but for negative numbers the - character is also included in the width. If the numbers are in decreasing order the resulting sequence will also be in decreasing order.

An expression of the form ‘{n1..n2..n3}’, where n1, n2, and n3 are integers, is expanded as above, but only every n3th number starting from n1 is output. If n3 is negative the numbers are output in reverse order, this is slightly different from simply swapping n1 and n2 in the case that the step n3 doesn’t evenly divide the range. Zero padding can be specified in any of the three numbers, specifying it in the third can be useful to pad for example ‘{-99..100..01}’ which is not possible to specify by putting a 0 on either of the first two numbers (i.e. pad to two characters).

An expression of the form ‘{c1..c2}’, where c1 and c2 are single characters (which may be multibyte characters), is expanded to every character in the range from c1 to c2 in whatever character sequence is used internally. For characters with code points below 128 this is US ASCII (this is the only case most users will need). If any intervening character is not printable, appropriate quotation is used to render it printable. If the character sequence is reversed, the output is in reverse order, e.g. ‘{d..a}’ is substituted as ‘d c b a’.

If a brace expression matches none of the above forms, it is left unchanged, unless the option BRACE_CCL (an abbreviation for ‘brace character class’) is set. In that case, it is expanded to a list of the individual characters between the braces sorted into the order of the characters in the ASCII character set (multibyte characters are not currently handled). The syntax is similar to a [...] expression in filename generation: ‘-’ is treated specially to denote a range of characters, but ‘^’ or ‘!’ as the first character is treated normally. For example, ‘{abcdef0-9}’ expands to 16 words 0 1 2 3 4 5 6 7 8 9 a b c d e f.

Note that brace expansion is not part of filename generation (globbing); an expression such as */{foo,bar} is split into two separate words */foo and */bar before filename generation takes place. In particular, note that this is liable to produce a ‘no match’ error if either of the two expressions does not match; this is to be contrasted with */(foo|bar), which is treated as a single pattern but otherwise has similar effects.

To combine brace expansion with array expansion, see the ${^spec} form described in the section Parameter Expansion above.

FILENAME EXPANSION

Each word is checked to see if it begins with an unquoted ‘~’. If it does, then the word up to a ‘/’, or the end of the word if there is no ‘/’, is checked to see if it can be substituted in one of the ways described here. If so, then the ‘~’ and the checked portion are replaced with the appropriate substitute value.

A ‘~’ by itself is replaced by the value of $HOME. A ‘~’ followed by a ‘+’ or a ‘-’ is replaced by current or previous working directory, respectively.

A ‘~’ followed by a number is replaced by the directory at that position in the directory stack. ‘~0’ is equivalent to ‘~+’, and ‘~1’ is the top of the stack. ‘~+’ followed by a number is replaced by the directory at that position in the directory stack. ‘~+0’ is equivalent to ‘~+’, and ‘~+1’ is the top of the stack. ‘~-’ followed by a number is replaced by the directory that many positions from the bottom of the stack. ‘~-0’ is the bottom of the stack. The PUSHD_MINUS option exchanges the effects of ‘~+’ and ‘~-’ where they are followed by a number.

    Dynamic named directories

If the function zsh_directory_name exists, or the shell variable zsh_directory_name_functions exists and contains an array of function names, then the functions are used to implement dynamic directory naming. The functions are tried in order until one returns status zero, so it is important that functions test whether they can handle the case in question and return an appropriate status.

A ‘~’ followed by a string namstr in unquoted square brackets is treated specially as a dynamic directory name. Note that the first unquoted closing square bracket always terminates namstr. The shell function is passed two arguments: the string n (for name) and namstr. It should either set the array reply to a single element which is the directory corresponding to the name and return status zero (executing an assignment as the last statement is usually sufficient), or it should return status non-zero. In the former case the element of reply is used as the directory; in the latter case the substitution is deemed to have failed. If all functions fail and the option NOMATCH is set, an error results.

The functions defined as above are also used to see if a directory can be turned into a name, for example when printing the directory stack or when expanding %~ in prompts. In this case each function is passed two arguments: the string d (for directory) and the candidate for dynamic naming. The function should either return non-zero status, if the directory cannot be named by the function, or it should set the array reply to consist of two elements: the first is the dynamic name for the directory (as would appear within ‘~[...]’), and the second is the prefix length of the directory to be replaced. For example, if the trial directory is /home/myname/src/zsh and the dynamic name for /home/myname/src (which has 16 characters) is s, then the function sets

reply=(s 16)

The directory name so returned is compared with possible static names for parts of the directory path, as described below; it is used if the prefix length matched (16 in the example) is longer than that matched by any static name.

It is not a requirement that a function implements both n and d calls; for example, it might be appropriate for certain dynamic forms of expansion not to be contracted to names. In that case any call with the first argument d should cause a non-zero status to be returned.

The completion system calls ‘zsh_directory_name c’ followed by equivalent calls to elements of the array zsh_directory_name_functions, if it exists, in order to complete dynamic names for directories. The code for this should be as for any other completion function as described in zshcompsys(1).

As a working example, here is a function that expands any dynamic names beginning with the string p: to directories below /home/pws/perforce. In this simple case a static name for the directory would be just as effective.

zsh_directory_name() {
  emulate -L zsh
  setopt extendedglob
  local -a match mbegin mend
  if [[ $1 = d ]]; then
    # turn the directory into a name
    if [[ $2 = (#b)(/home/pws/perforce/)([^/]##)* ]]; then
      typeset -ga reply
      reply=(p:$match[2] $(( ${#match[1]} + ${#match[2]} )) )
    else
      return 1
    fi
  elif [[ $1 = n ]]; then
    # turn the name into a directory
    [[ $2 != (#b)p:(?*) ]] && return 1
    typeset -ga reply
    reply=(/home/pws/perforce/$match[1])
  elif [[ $1 = c ]]; then
    # complete names
    local expl
    local -a dirs
    dirs=(/home/pws/perforce/*(/:t))
    dirs=(p:${^dirs})
    _wanted dynamic-dirs expl ’dynamic directory’ compadd -S\] -a dirs
    return
  else
    return 1
  fi
  return 0
}

    Static named directories

A ‘~’ followed by anything not already covered consisting of any number of alphanumeric characters or underscore (‘_’), hyphen (‘-’), or dot (‘.’) is looked up as a named directory, and replaced by the value of that named directory if found. Named directories are typically home directories for users on the system. They may also be defined if the text after the ‘~’ is the name of a string shell parameter whose value begins with a ‘/’. Note that trailing slashes will be removed from the path to the directory (though the original parameter is not modified).

It is also possible to define directory names using the -d option to the hash builtin.

When the shell prints a path (e.g. when expanding %~ in prompts or when printing the directory stack), the path is checked to see if it has a named directory as its prefix. If so, then the prefix portion is replaced with a ‘~’ followed by the name of the directory. The shorter of the two ways of referring to the directory is used, i.e. either the directory name or the full path; the name is used if they are the same length. The parameters $PWD and $OLDPWD are never abbreviated in this fashion.

    ‘=’ expansion

If a word begins with an unquoted ‘=’ and the EQUALS option is set, the remainder of the word is taken as the name of a command. If a command exists by that name, the word is replaced by the full pathname of the command.

    Notes

Filename expansion is performed on the right hand side of a parameter assignment, including those appearing after commands of the typeset family. In this case, the right hand side will be treated as a colon-separated list in the manner of the PATH parameter, so that a ‘~’ or an ‘=’ following a ‘:’ is eligible for expansion. All such behaviour can be disabled by quoting the ‘~’, the ‘=’, or the whole expression (but not simply the colon); the EQUALS option is also respected.

If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in the form ‘identifier=expression’ becomes eligible for file expansion as described in the previous paragraph. Quoting the first ‘=’ also inhibits this.

FILENAME GENERATION

If a word contains an unquoted instance of one of the characters ‘*’, ‘(’, ‘|’, ‘<’, ‘[’, or ‘?’, it is regarded as a pattern for filename generation, unless the GLOB option is unset. If the EXTENDED_GLOB option is set, the ‘^’ and ‘#’ characters also denote a pattern; otherwise they are not treated specially by the shell.

The word is replaced with a list of sorted filenames that match the pattern. If no matching pattern is found, the shell gives an error message, unless the NULL_GLOB option is set, in which case the word is deleted; or unless the NOMATCH option is unset, in which case the word is left unchanged.

In filename generation, the character ‘/’ must be matched explicitly; also, a ‘.’ must be matched explicitly at the beginning of a pattern or after a ‘/’, unless the GLOB_DOTS option is set. No filename generation pattern matches the files ‘.’ or ‘..’. In other instances of pattern matching, the ‘/’ and ‘.’ are not treated specially.

    Glob Operators

* Matches any string, including the null string.
? Matches any character.
[...] Matches any of the enclosed characters. Ranges of characters can be specified by separating two characters by a ‘-’. A ‘-’ or ‘]’ may be matched by including it as the first character in the list. There are also several named classes of characters, in the form ‘[:name:]’ with the following meanings. The first set use the macros provided by the operating system to test for the given character combinations, including any modifications due to local language settings, see ctype(3):

[:alnum:]
  The character is alphanumeric
[:alpha:]
  The character is alphabetic
[:ascii:]
  The character is 7-bit, i.e. is a single-byte character without the top bit set.
[:blank:]
  The character is either space or tab
[:cntrl:]
  The character is a control character
[:digit:]
  The character is a decimal digit
[:graph:]
  The character is a printable character other than whitespace
[:lower:]
  The character is a lowercase letter
[:print:]
  The character is printable
[:punct:]
  The character is printable but neither alphanumeric nor whitespace
[:space:]
  The character is whitespace
[:upper:]
  The character is an uppercase letter
[:xdigit:]
  The character is a hexadecimal digit
Another set of named classes is handled internally by the shell and is not sensitive to the locale:
[:IDENT:]
  The character is allowed to form part of a shell identifier, such as a parameter name
[:IFS:] The character is used as an input field separator, i.e. is contained in the IFS parameter
[:IFSSPACE:]
  The character is an IFS white space character; see the documentation for IFS in the zshparam(1) manual page.
[:INCOMPLETE:]
  Matches a byte that starts an incomplete multibyte character. Note that there may be a sequence of more than one bytes that taken together form the prefix of a multibyte character. To test for a potentially incomplete byte sequence, use the pattern ‘[[:INCOMPLETE:]]*’. This will never match a sequence starting with a valid multibyte character.
[:INVALID:]
  Matches a byte that does not start a valid multibyte character. Note this may be a continuation byte of an incomplete multibyte character as any part of a multibyte string consisting of invalid and incomplete multibyte characters is treated as single bytes.
[:WORD:]
  The character is treated as part of a word; this test is sensitive to the value of the WORDCHARS parameter
Note that the square brackets are additional to those enclosing the whole set of characters, so to test for a single alphanumeric character you need ‘[[:alnum:]]’. Named character sets can be used alongside other types, e.g. ‘[[:alpha:]0-9]’.

[^...]
[!...]
Like [...], except that it matches any character which is not in the given set.
<[x]-[y]>
  Matches any number in the range x to y, inclusive. Either of the numbers may be omitted to make the range open-ended; hence ‘<->’ matches any number. To match individual digits, the [...] form is more efficient.

Be careful when using other wildcards adjacent to patterns of this form; for example, <0-9>* will actually match any number whatsoever at the start of the string, since the ‘<0-9>’ will match the first digit, and the ‘*’ will match any others. This is a trap for the unwary, but is in fact an inevitable consequence of the rule that the longest possible match always succeeds. Expressions such as ‘<0-9>[^[:digit:]]*’ can be used instead.

(...) Matches the enclosed pattern. This is used for grouping. If the KSH_GLOB option is set, then a ‘@’, ‘*’, ‘+’, ‘?’ or ‘!’ immediately preceding the ‘(’ is treated specially, as detailed below. The option SH_GLOB prevents bare parentheses from being used in this way, though the KSH_GLOB option is still available.

Note that grouping cannot extend over multiple directories: it is an error to have a ‘/’ within a group (this only applies for patterns used in filename generation). There is one exception: a group of the form (pat/)# appearing as a complete path segment can match a sequence of directories. For example, foo/(a*/)#bar matches foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.

x|y Matches either x or y. This operator has lower precedence than any other. The ‘|’ character must be within parentheses, to avoid interpretation as a pipeline.
^x (Requires EXTENDED_GLOB to be set.) Matches anything except the pattern x. This has a higher precedence than ‘/’, so ‘^foo/bar’ will search directories in ‘.’ except ‘./foo’ for a file named ‘bar’.
x~y (Requires EXTENDED_GLOB to be set.) Match anything that matches the pattern x but does not match y. This has lower precedence than any operator except ‘|’, so ‘*/*~foo/bar’ will search for all files in all directories in ‘.’ and then exclude ‘foo/bar’ if there was such a match. Multiple patterns can be excluded by ‘foo~bar~baz’. In the exclusion pattern (y), ‘/’ and ‘.’ are not treated specially the way they usually are in globbing.
x# (Requires EXTENDED_GLOB to be set.) Matches zero or more occurrences of the pattern x. This operator has high precedence; ‘12#’ is equivalent to ‘1(2#)’, rather than ‘(12)#’. It is an error for an unquoted ‘#’ to follow something which cannot be repeated; this includes an empty string, a pattern already followed by ‘##’, or parentheses when part of a KSH_GLOB pattern (for example, ‘!(foo)#’ is invalid and must be replaced by ‘*(!(foo))’).
x## (Requires EXTENDED_GLOB to be set.) Matches one or more occurrences of the pattern x. This operator has high precedence; ‘12##’ is equivalent to ‘1(2##)’, rather than ‘(12)##’. No more than two active ‘#’ characters may appear together. (Note the potential clash with glob qualifiers in the form ‘1(2##)’ which should therefore be avoided.)

    ksh-like Glob Operators

If the KSH_GLOB option is set, the effects of parentheses can be modified by a preceding ‘@’, ‘*’, ‘+’, ‘?’ or ‘!’. This character need not be unquoted to have special effects, but the ‘(’ must be.

@(...) Match the pattern in the parentheses. (Like ‘(...)’.)
*(...) Match any number of occurrences. (Like ‘(...)#’, except that recursive directory searching is not supported.)
+(...) Match at least one occurrence. (Like ‘(...)##’, except that recursive directory searching is not supported.)
?(...) Match zero or one occurrence. (Like ‘(|...)’.)
!(...) Match anything but the expression in parentheses. (Like ‘(^(...))’.)

    Precedence

The precedence of the operators given above is (highest) ‘^’, ‘/’, ‘~’, ‘|’ (lowest); the remaining operators are simply treated from left to right as part of a string, with ‘#’ and ‘##’ applying to the shortest possible preceding unit (i.e. a character, ‘?’, ‘[...]’, ‘<...>’, or a parenthesised expression). As mentioned above, a ‘/’ used as a directory separator may not appear inside parentheses, while a ‘|’ must do so; in patterns used in other contexts than filename generation (for example, in case statements and tests within ‘[[...]]’), a ‘/’ is not special; and ‘/’ is also not special after a ‘~’ appearing outside parentheses in a filename pattern.

    Globbing Flags

There are various flags which affect any text to their right up to the end of the enclosing group or to the end of the pattern; they require the EXTENDED_GLOB option. All take the form (#X) where X may have one of the following forms:

i Case insensitive: upper or lower case characters in the pattern match upper or lower case characters.
l Lower case characters in the pattern match upper or lower case characters; upper case characters in the pattern still only match upper case characters.
I Case sensitive: locally negates the effect of i or l from that point on.
b Activate backreferences for parenthesised groups in the pattern; this does not work in filename generation. When a pattern with a set of active parentheses is matched, the strings matched by the groups are stored in the array $match, the indices of the beginning of the matched parentheses in the array $mbegin, and the indices of the end in the array $mend, with the first element of each array corresponding to the first parenthesised group, and so on. These arrays are not otherwise special to the shell. The indices use the same convention as does parameter substitution, so that elements of $mend and $mbegin may be used in subscripts; the KSH_ARRAYS option is respected. Sets of globbing flags are not considered parenthesised groups; only the first nine active parentheses can be referenced.

For example,

 
foo="a string with a message"
if [[ $foo = (a|an)’ ’(#b)(*)’ ’* ]]; then
  print ${foo[$mbegin[1],$mend[1]]}
fi

prints ‘string with a’. Note that the first parenthesis is before the (#b) and does not create a backreference.

Backreferences work with all forms of pattern matching other than filename generation, but note that when performing matches on an entire array, such as ${array#pattern}, or a global substitution, such as ${param//pat/repl}, only the data for the last match remains available. In the case of global replacements this may still be useful. See the example for the m flag below.

The numbering of backreferences strictly follows the order of the opening parentheses from left to right in the pattern string, although sets of parentheses may be nested. There are special rules for parentheses followed by ‘#’ or ‘##’. Only the last match of the parenthesis is remembered: for example, in ‘[[ abab = (#b)([ab])# ]]’, only the final ‘b’ is stored in match[1]. Thus extra parentheses may be necessary to match the complete segment: for example, use ‘X((ab|cd)#)Y’ to match a whole string of either ‘ab’ or ‘cd’ between ‘X’ and ‘Y’, using the value of $match[1] rather than $match[2].

If the match fails none of the parameters is altered, so in some cases it may be necessary to initialise them beforehand. If some of the backreferences fail to match -- which happens if they are in an alternate branch which fails to match, or if they are followed by # and matched zero times -- then the matched string is set to the empty string, and the start and end indices are set to -1.

Pattern matching with backreferences is slightly slower than without.

B Deactivate backreferences, negating the effect of the b flag from that point on.
cN,M The flag (#cN,M) can be used anywhere that the # or ## operators can be used except in the expressions ‘(*/)#’ and ‘(*/)##’ in filename generation, where ‘/’ has special meaning; it cannot be combined with other globbing flags and a bad pattern error occurs if it is misplaced. It is equivalent to the form {N,M} in regular expressions. The previous character or group is required to match between N and M times, inclusive. The form (#cN) requires exactly N matches; (#c,M) is equivalent to specifying N as 0; (#cN,) specifies that there is no maximum limit on the number of matches.
m Set references to the match data for the entire string matched; this is similar to backreferencing and does not work in filename generation. The flag must be in effect at the end of the pattern, i.e. not local to a group. The parameters $MATCH, $MBEGIN and $MEND will be set to the string matched and to the indices of the beginning and end of the string, respectively. This is most useful in parameter substitutions, as otherwise the string matched is obvious.

For example,

 
arr=(veldt jynx grimps waqf zho buck)
print ${arr//(#m)[aeiou]/${(U)MATCH}}

forces all the matches (i.e. all vowels) into uppercase, printing ‘vEldt jynx grImps wAqf zhO bUck’.

Unlike backreferences, there is no speed penalty for using match references, other than the extra substitutions required for the replacement strings in cases such as the example shown.

M Deactivate the m flag, hence no references to match data will be created.
anum Approximate matching: num errors are allowed in the string matched by the pattern. The rules for this are described in the next subsection.
s, e Unlike the other flags, these have only a local effect, and each must appear on its own: ‘(#s)’ and ‘(#e)’ are the only valid forms. The ‘(#s)’ flag succeeds only at the start of the test string, and the ‘(#e)’ flag succeeds only at the end of the test string; they correspond to ‘^’ and ‘$’ in standard regular expressions. They are useful for matching path segments in patterns other than those in filename generation (where path segments are in any case treated separately). For example, ‘*((#s)|/)test((#e)|/)*’ matches a path segment ‘test’ in any of the following strings: test, test/at/start, at/end/test, in/test/middle.

Another use is in parameter substitution; for example ‘${array/(#s)A*Z(#e)}’ will remove only elements of an array which match the complete pattern ‘A*Z’. There are other ways of performing many operations of this type, however the combination of the substitution operations ‘/’ and ‘//’ with the ‘(#s)’ and ‘(#e)’ flags provides a single simple and memorable method.

Note that assertions of the form ‘(^(#s))’ also work, i.e. match anywhere except at the start of the string, although this actually means ‘anything except a zero-length portion at the start of the string’; you need to use ‘(""~(#s))’ to match a zero-length portion of the string not at the start.

q A ‘q’ and everything up to the closing parenthesis of the globbing flags are ignored by the pattern matching code. This is intended to support the use of glob qualifiers, see below. The result is that the pattern ‘(#b)(*).c(#q.)’ can be used both for globbing and for matching against a string. In the former case, the ‘(#q.)’ will be treated as a glob qualifier and the ‘(#b)’ will not be useful, while in the latter case the ‘(#b)’ is useful for backreferences and the ‘(#q.)’ will be ignored. Note that colon modifiers in the glob qualifiers are also not applied in ordinary pattern matching.
u Respect the current locale in determining the presence of multibyte characters in a pattern, provided the shell was compiled with MULTIBYTE_SUPPORT. This overrides the MULTIBYTE option; the default behaviour is taken from the option. Compare U. (Mnemonic: typically multibyte characters are from Unicode in the UTF-8 encoding, although any extension of ASCII supported by the system library may be used.)
U All characters are considered to be a single byte long. The opposite of u. This overrides the MULTIBYTE option.
For example, the test string fooxx can be matched by the pattern (#i)FOOXX, but not by (#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X. The string (#ia2)readme specifies case-insensitive matching of readme with up to two errors.

When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB must be set and the left parenthesis should be preceded by @. Note also that the flags do not affect letters inside [...] groups, in other words (#i)[a-z] still matches only lowercase letters. Finally, note that when examining whole paths case-insensitively every directory must be searched for all files which match, so that a pattern of the form (#i)/foo/bar/... is potentially slow.

    Approximate Matching

When matching approximately, the shell keeps a count of the errors found, which cannot exceed the number specified in the (#anum) flags. Four types of error are recognised:

1. Different characters, as in fooxbar and fooybar.
2. Transposition of characters, as in banana and abnana.
3. A character missing in the target string, as with the pattern road and target string rod.
4. An extra character appearing in the target string, as with stove and strove.
Thus, the pattern (#a3)abcd matches dcba, with the errors occurring by using the first rule twice and the second once, grouping the string as [d][cb][a] and [a][bc][d].

Non-literal parts of the pattern must match exactly, including characters in character ranges: hence (#a1)??? matches strings of length four, by applying rule 4 to an empty part of the pattern, but not strings of length two, since all the ? must match. Other characters which must match exactly are initial dots in filenames (unless the GLOB_DOTS option is set), and all slashes in filenames, so that a/bc is two errors from ab/c (the slash cannot be transposed with another character). Similarly, errors are counted separately for non-contiguous strings in the pattern, so that (ab|cd)ef is two errors from aebf.

When using exclusion via the ~ operator, approximate matching is treated entirely separately for the excluded part and must be activated separately. Thus, (#a1)README~READ_ME matches READ.ME but not READ_ME, as the trailing READ_ME is matched without approximation. However, (#a1)README~(#a1)READ_ME does not match any pattern of the form READ?ME as all such forms are now excluded.

Apart from exclusions, there is only one overall error count; however, the maximum errors allowed may be altered locally, and this can be delimited by grouping. For example, (#a1)cat((#a0)dog)fox allows one error in total, which may not occur in the dog section, and the pattern (#a1)cat(#a0)dog(#a1)fox is equivalent. Note that the point at which an error is first found is the crucial one for establishing whether to use approximation; for example, (#a1)abc(#a0)xyz will not match abcdxyz, because the error occurs at the ‘x’, where approximation is turned off.

Entire path segments may be matched approximately, so that ‘(#a1)/foo/d/is/available/at/the/bar’ allows one error in any path segment. This is much less efficient than without the (#a1), however, since every directory in the path must be scanned for a possible approximate match. It is best to place the (#a1) after any path segments which are known to be correct.

    Recursive Globbing

A pathname component of the form ‘(foo/)#’ matches a path consisting of zero or more directories matching the pattern foo.

As a shorthand, ‘**/’ is equivalent to ‘(*/)#’; note that this therefore matches files in the current directory as well as subdirectories. Thus:

ls (*/)#bar

or

ls **/bar

does a recursive directory search for files named ‘bar’ (potentially including the file ‘bar’ in the current directory). This form does not follow symbolic links; the alternative form ‘***/’ does, but is otherwise identical. Neither of these can be combined with other forms of globbing within the same path segment; in that case, the ‘*’ operators revert to their usual effect.

Even shorter forms are available when the option GLOB_STAR_SHORT is set. In that case if no / immediately follows a ** or *** they are treated as if both a / plus a further * are present. Hence:

setopt GLOBSTARSHORT
ls **.c

is equivalent to

ls **/*.c

    Glob Qualifiers

Patterns used for filename generation may end in a list of qualifiers enclosed in parentheses. The qualifiers specify which filenames that otherwise match the given pattern will be inserted in the argument list.

If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses containing no ‘|’ or ‘(’ characters (or ‘~’ if it is special) is taken as a set of glob qualifiers. A glob subexpression that would normally be taken as glob qualifiers, for example ‘(^x)’, can be forced to be treated as part of the glob pattern by doubling the parentheses, in this case producing ‘((^x))’.

If the option EXTENDED_GLOB is set, a different syntax for glob qualifiers is available, namely ‘(#qx)’ where x is any of the same glob qualifiers used in the other format. The qualifiers must still appear at the end of the pattern. However, with this syntax multiple glob qualifiers may be chained together. They are treated as a logical AND of the individual sets of flags. Also, as the syntax is unambiguous, the expression will be treated as glob qualifiers just as long any parentheses contained within it are balanced; appearance of ‘|’, ‘(’ or ‘~’ does not negate the effect. Note that qualifiers will be recognised in this form even if a bare glob qualifier exists at the end of the pattern, for example ‘*(#q*)(.)’ will recognise executable regular files if both options are set; however, mixed syntax should probably be avoided for the sake of clarity. Note that within conditions using the ‘[[’ form the presence of a parenthesised expression (#q...) at the end of a string indicates that globbing should be performed; the expression may include glob qualifiers, but it is also valid if it is simply (#q). This does not apply to the right hand side of pattern match operators as the syntax already has special significance.

A qualifier may be any one of the following:

/ directories
F ‘full’ (i.e. non-empty) directories. Note that the opposite sense (^F) expands to empty directories and all non-directories. Use (/^F) for empty directories.
. plain files
@ symbolic links
= sockets
p named pipes (FIFOs)
* executable plain files (0100 or 0010 or 0001)
% device files (character or block special)
%b block special files
%c character special files
r owner-readable files (0400)
w owner-writable files (0200)
x owner-executable files (0100)
A group-readable files (0040)
I group-writable files (0020)
E group-executable files (0010)
R world-readable files (0004)
W world-writable files (0002)
X world-executable files (0001)
s setuid files (04000)
S setgid files (02000)
t files with the sticky bit (01000)
fspec files with access rights matching spec. This spec may be a octal number optionally preceded by a ‘=’, a ‘+’, or a ‘-’. If none of these characters is given, the behavior is the same as for ‘=’. The octal number describes the mode bits to be expected, if combined with a ‘=’, the value given must match the file-modes exactly, with a ‘+’, at least the bits in the given number must be set in the file-modes, and with a ‘-’, the bits in the number must not be set. Giving a ‘?’ instead of a octal digit anywhere in the number ensures that the corresponding bits in the file-modes are not checked, this is only useful in combination with ‘=’.

If the qualifier ‘f’ is followed by any other character anything up to the next matching character (‘[’, ‘{’, and ‘<’ match ‘]’, ‘}’, and ‘>’ respectively, any other character matches itself) is taken as a list of comma-separated sub-specs. Each sub-spec may be either an octal number as described above or a list of any of the characters ‘u’, ‘g’, ‘o’, and ‘a’, followed by a ‘=’, a ‘+’, or a ‘-’, followed by a list of any of the characters ‘r’, ‘w’, ‘x’, ‘s’, and ‘t’, or an octal digit. The first list of characters specify which access rights are to be checked. If a ‘u’ is given, those for the owner of the file are used, if a ‘g’ is given, those of the group are checked, a ‘o’ means to test those of other users, and the ‘a’ says to test all three groups. The ‘=’, ‘+’, and ‘-’ again says how the modes are to be checked and have the same meaning as described for the first form above. The second list of characters finally says which access rights are to be expected: ‘r’ for read access, ‘w’ for write access, ‘x’ for the right to execute the file (or to search a directory), ‘s’ for the setuid and setgid bits, and ‘t’ for the sticky bit.

Thus, ‘*(f70?)’ gives the files for which the owner has read, write, and execute permission, and for which other group members have no rights, independent of the permissions for other users. The pattern ‘*(f-100)’ gives all files for which the owner does not have execute permission, and ‘*(f:gu+w,o-rx:)’ gives the files for which the owner and the other members of the group have at least write permission, and for which other users don’t have read or execute permission.

estring
+cmd
  The string will be executed as shell code. The filename will be included in the list if and only if the code returns a zero status (usually the status of the last command).

In the first form, the first character after the ‘e’ will be used as a separator and anything up to the next matching separator will be taken as the string; ‘[’, ‘{’, and ‘<’ match ‘]’, ‘}’, and ‘>’, respectively, while any other character matches itself. Note that expansions must be quoted in the string to prevent them from being expanded before globbing is done. string is then executed as shell code. The string globqual is appended to the array zsh_eval_context the duration of execution.

During the execution of string the filename currently being tested is available in the parameter REPLY; the parameter may be altered to a string to be inserted into the list instead of the original filename. In addition, the parameter reply may be set to an array or a string, which overrides the value of REPLY. If set to an array, the latter is inserted into the command line word by word.

For example, suppose a directory contains a single file ‘lonely’. Then the expression ‘*(e:’reply=(${REPLY}{1,2})’:)’ will cause the words ‘lonely1’ and ‘lonely2’ to be inserted into the command line. Note the quoting of string.

The form +cmd has the same effect, but no delimiters appear around cmd. Instead, cmd is taken as the longest sequence of characters following the + that are alphanumeric or underscore. Typically cmd will be the name of a shell function that contains the appropriate test. For example,

 
nt() { [[ $REPLY -nt $NTREF ]] }
NTREF=reffile
ls -l *(+nt)

lists all files in the directory that have been modified more recently than reffile.

ddev files on the device dev
l[-|+]ct
  files having a link count less than ct (-), greater than ct (+), or equal to ct
U files owned by the effective user ID
G files owned by the effective group ID
uid files owned by user ID id if that is a number. Otherwise, id specifies a user name: the character after the ‘u’ will be taken as a separator and the string between it and the next matching separator will be taken as a user name. The starting separators ‘[’, ‘{’, and ‘<’ match the final separators ‘]’, ‘}’, and ‘>’, respectively; any other character matches itself. The selected files are those owned by this user. For example, ‘u:foo:’ or ‘u[foo]’ selects files owned by user ‘foo’.
gid like uid but with group IDs or names
a[Mwhms][-|+]n
  files accessed exactly n days ago. Files accessed within the last n days are selected using a negative value for n (-n). Files accessed more than n days ago are selected by a positive n value (+n). Optional unit specifiers ‘M’, ‘w’, ‘h’, ‘m’ or ‘s’ (e.g. ‘ah5’) cause the check to be performed with months (of 30 days), weeks, hours, minutes or seconds instead of days, respectively. An explicit ‘d’ for days is also allowed.

Any fractional part of the difference between the access time and the current part in the appropriate units is ignored in the comparison. For instance, ‘echo *(ah-5)’ would echo files accessed within the last five hours, while ‘echo *(ah+5)’ would echo files accessed at least six hours ago, as times strictly between five and six hours are treated as five hours.

m[Mwhms][-|+]n
  like the file access qualifier, except that it uses the file modification time.
c[Mwhms][-|+]n
  like the file access qualifier, except that it uses the file inode change time.
L[+|-]n
  files less than n bytes (-), more than n bytes (+), or exactly n bytes in length.

If this flag is directly followed by a size specifierk’ (‘K’), ‘m’ (‘M’), or ‘p’ (‘P’) (e.g. ‘Lk-50’) the check is performed with kilobytes, megabytes, or blocks (of 512 bytes) instead. (On some systems additional specifiers are available for gigabytes, ‘g’ or ‘G’, and terabytes, ‘t’ or ‘T’.) If a size specifier is used a file is regarded as "exactly" the size if the file size rounded up to the next unit is equal to the test size. Hence ‘*(Lm1)’ matches files from 1 byte up to 1 Megabyte inclusive. Note also that the set of files "less than" the test size only includes files that would not match the equality test; hence ‘*(Lm-1)’ only matches files of zero size.

^ negates all qualifiers following it
- toggles between making the qualifiers work on symbolic links (the default) and the files they point to
M sets the MARK_DIRS option for the current pattern
T appends a trailing qualifier mark to the filenames, analogous to the LIST_TYPES option, for the current pattern (overrides M)
N sets the NULL_GLOB option for the current pattern
D sets the GLOB_DOTS option for the current pattern
n sets the NUMERIC_GLOB_SORT option for the current pattern
Yn enables short-circuit mode: the pattern will expand to at most n filenames. If more than n matches exist, only the first n matches in directory traversal order will be considered.

Implies oN when no oc qualifier is used.

oc specifies how the names of the files should be sorted. If c is n they are sorted by name; if it is L they are sorted depending on the size (length) of the files; if l they are sorted by the number of links; if a, m, or c they are sorted by the time of the last access, modification, or inode change respectively; if d, files in subdirectories appear before those in the current directory at each level of the search -- this is best combined with other criteria, for example ‘odon’ to sort on names for files within the same directory; if N, no sorting is performed. Note that a, m, and c compare the age against the current time, hence the first name in the list is the youngest file. Also note that the modifiers ^ and - are used, so ‘*(^-oL)’ gives a list of all files sorted by file size in descending order, following any symbolic links. Unless oN is used, multiple order specifiers may occur to resolve ties.

The default sorting is n (by name) unless the Y glob qualifier is used, in which case it is N (unsorted).

oe and o+ are special cases; they are each followed by shell code, delimited as for the e glob qualifier and the + glob qualifier respectively (see above). The code is executed for each matched file with the parameter REPLY set to the name of the file on entry and globsort appended to zsh_eval_context. The code should modify the parameter REPLY in some fashion. On return, the value of the parameter is used instead of the file name as the string on which to sort. Unlike other sort operators, oe and o+ may be repeated, but note that the maximum number of sort operators of any kind that may appear in any glob expression is 12.

Oc like ‘o’, but sorts in descending order; i.e. ‘*(^oc)’ is the same as ‘*(Oc)’ and ‘*(^Oc)’ is the same as ‘*(oc)’; ‘Od’ puts files in the current directory before those in subdirectories at each level of the search.
[beg[,end]]
  specifies which of the matched filenames should be included in the returned list. The syntax is the same as for array subscripts. beg and the optional end may be mathematical expressions. As in parameter subscripting they may be negative to make them count from the last match backward. E.g.: ‘*(-OL[1,3])’ gives a list of the names of the three largest files.
Pstring
  The string will be prepended to each glob match as a separate word. string is delimited in the same way as arguments to the e glob qualifier described above. The qualifier can be repeated; the words are prepended separately so that the resulting command line contains the words in the same order they were given in the list of glob qualifiers.

A typical use for this is to prepend an option before all occurrences of a file name; for example, the pattern ‘*(P:-f:)’ produces the command line arguments ‘-f file1 -f file2 ...’

If the modifier ^ is active, then string will be appended instead of prepended. Prepending and appending is done independently so both can be used on the same glob expression; for example by writing ‘*(P:foo:^P:bar:^P:baz:)’ which produces the command line arguments ‘foo baz file1 bar ...’

More than one of these lists can be combined, separated by commas. The whole list matches if at least one of the sublists matches (they are ‘or’ed, the qualifiers in the sublists are ‘and’ed). Some qualifiers, however, affect all matches generated, independent of the sublist in which they are given. These are the qualifiers ‘M’, ‘T’, ‘N’, ‘D’, ‘n’, ‘o’, ‘O’ and the subscripts given in brackets (‘[...]’).
If a ‘:’ appears in a qualifier list, the remainder of the expression in parenthesis is interpreted as a modifier (see the section ‘Modifiers’ in the section ‘History Expansion’). Each modifier must be introduced by a separate ‘:’. Note also that the result after modification does not have to be an existing file. The name of any existing file can be followed by a modifier of the form ‘(:...)’ even if no actual filename generation is performed, although note that the presence of the parentheses causes the entire expression to be subjected to any global pattern matching options such as NULL_GLOB. Thus:

 
ls *(-/)

lists all directories and symbolic links that point to directories, and

 
ls *(-@)

lists all broken symbolic links, and

 
ls *(%W)

lists all world-writable device files in the current directory, and

 
ls *(W,X)

lists all files in the current directory that are world-writable or world-executable, and

 
echo /tmp/foo*(u0^@:t)

outputs the basename of all root-owned files beginning with the string ‘foo’ in /tmp, ignoring symlinks, and

 
ls *.*~(lex|parse).[ch](^D^l1)

lists all files having a link count of one whose names contain a dot (but not those starting with a dot, since GLOB_DOTS is explicitly switched off) except for lex.c, lex.h, parse.c and parse.h.

 
print b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)

demonstrates how colon modifiers and other qualifiers may be chained together. The ordinary qualifier ‘.’ is applied first, then the colon modifiers in order from left to right. So if EXTENDED_GLOB is set and the base pattern matches the regular file builtin.pro, the shell will print ‘shmiltin.shmo’.

NAME

zshparam - zsh parameters

DESCRIPTION

A parameter has a name, a value, and a number of attributes. A name may be any sequence of alphanumeric characters and underscores, or the single characters ‘*’, ‘@’, ‘#’, ‘?’, ‘-’, ‘$’, or ‘!’. A parameter whose name begins with an alphanumeric or underscore is also referred to as a variable.

The attributes of a parameter determine the type of its value, often referred to as the parameter type or variable type, and also control other processing that may be applied to the value when it is referenced. The value type may be a scalar (a string, an integer, or a floating point number), an array (indexed numerically), or an associative array (an unordered set of name-value pairs, indexed by name, also referred to as a hash).

Named scalar parameters may have the exported, -x, attribute, to copy them into the process environment, which is then passed from the shell to any new processes that it starts. Exported parameters are called environment variables. The shell also imports environment variables at startup time and automatically marks the corresponding parameters as exported. Some environment variables are not imported for reasons of security or because they would interfere with the correct operation of other shell features.

Parameters may also be special, that is, they have a predetermined meaning to the shell. Special parameters cannot have their type changed or their readonly attribute turned off, and if a special parameter is unset, then later recreated, the special properties will be retained.

To declare the type of a parameter, or to assign a string or numeric value to a scalar parameter, use the typeset builtin.

The value of a scalar parameter may also be assigned by writing:

name=value

In scalar assignment, value is expanded as a single string, in which the elements of arrays are joined together; filename expansion is not performed unless the option GLOB_ASSIGN is set.

When the integer attribute, -i, or a floating point attribute, -E or -F, is set for name, the value is subject to arithmetic evaluation. Furthermore, by replacing ‘=’ with ‘+=’, a parameter can be incremented or appended to. See the section ‘Array Parameters’ and Arithmetic Evaluation (in zshmisc(1)) for additional forms of assignment.

Note that assignment may implicitly change the attributes of a parameter. For example, assigning a number to a variable in arithmetic evaluation may change its type to integer or float, and with GLOB_ASSIGN assigning a pattern to a variable may change its type to an array.

To reference the value of a parameter, write ‘$name’ or ‘${name}’. See Parameter Expansion in zshexpn(1) for complete details. That section also explains the effect of the difference between scalar and array assignment on parameter expansion.

ARRAY PARAMETERS

To assign an array value, write one of:

set -A name value ...

name=(value ...)

If no parameter name exists, an ordinary array parameter is created. If the parameter name exists and is a scalar, it is replaced by a new array. To append to an array without changing the existing values, use the syntax:

name+=(value ...)

Within the parentheses on the right hand side of either form of the assignment, newlines and semicolons are treated the same as white space, separating individual values. Any consecutive sequence of such characters has the same effect.

Ordinary array parameters may also be explicitly declared with:

typeset -a name

Associative arrays must be declared before assignment, by using:

typeset -A name

When name refers to an associative array, the list in an assignment is interpreted as alternating keys and values:

set -A name key value ...

name=(key value ...)

Every key must have a value in this case. Note that this assigns to the entire array, deleting any elements that do not appear in the list. The append syntax may also be used with an associative array:

name+=(key value ...)

This adds a new key/value pair if the key is not already present, and replaces the value for the existing key if it is.

To create an empty array (including associative arrays), use one of:

set -A name

name=()

    Array Subscripts

Individual elements of an array may be selected using a subscript. A subscript of the form ‘[exp]’ selects the single element exp, where exp is an arithmetic expression which will be subject to arithmetic expansion as if it were surrounded by ‘$((...))’. The elements are numbered beginning with 1, unless the KSH_ARRAYS option is set in which case they are numbered from zero.

Subscripts may be used inside braces used to delimit a parameter name, thus ‘${foo[2]}’ is equivalent to ‘$foo[2]’. If the KSH_ARRAYS option is set, the braced form is the only one that works, as bracketed expressions otherwise are not treated as subscripts.

If the KSH_ARRAYS option is not set, then by default accesses to an array element with a subscript that evaluates to zero return an empty string, while an attempt to write such an element is treated as an error. For backward compatibility the KSH_ZERO_SUBSCRIPT option can be set to cause subscript values 0 and 1 to be equivalent; see the description of the option in zshoptions(1).

The same subscripting syntax is used for associative arrays, except that no arithmetic expansion is applied to exp. However, the parsing rules for arithmetic expressions still apply, which affects the way that certain special characters must be protected from interpretation. See Subscript Parsing below for details.

A subscript of the form ‘[*]’ or ‘[@]’ evaluates to all elements of an array; there is no difference between the two except when they appear within double quotes. ‘"$foo[*]"’ evaluates to ‘"$foo[1] $foo[2] ..."’, whereas ‘"$foo[@]"’ evaluates to ‘"$foo[1]" "$foo[2]" ...’. For associative arrays, ‘[*]’ or ‘[@]’ evaluate to all the values, in no particular order. Note that this does not substitute the keys; see the documentation for the ‘k’ flag under Parameter Expansion Flags in zshexpn(1) for complete details. When an array parameter is referenced as ‘$name’ (with no subscript) it evaluates to ‘$name[*]’, unless the KSH_ARRAYS option is set in which case it evaluates to ‘${name[0]}’ (for an associative array, this means the value of the key ‘0’, which may not exist even if there are values for other keys).

A subscript of the form ‘[exp1,exp2]’ selects all elements in the range exp1 to exp2, inclusive. (Associative arrays are unordered, and so do not support ranges.) If one of the subscripts evaluates to a negative number, say -n, then the nth element from the end of the array is used. Thus ‘$foo[-3]’ is the third element from the end of the array foo, and ‘$foo[1,-1]’ is the same as ‘$foo[*]’.

Subscripting may also be performed on non-array values, in which case the subscripts specify a substring to be extracted. For example, if FOO is set to ‘foobar’, then ‘echo $FOO[2,5]’ prints ‘ooba’. Note that some forms of subscripting described below perform pattern matching, and in that case the substring extends from the start of the match of the first subscript to the end of the match of the second subscript. For example,

string="abcdefghijklm"
print ${string[(r)d?,(r)h?]}

prints ‘defghi’. This is an obvious generalisation of the rule for single-character matches. For a single subscript, only a single character is referenced (not the range of characters covered by the match).

Note that in substring operations the second subscript is handled differently by the r and R subscript flags: the former takes the shortest match as the length and the latter the longest match. Hence in the former case a * at the end is redundant while in the latter case it matches the whole remainder of the string. This does not affect the result of the single subscript case as here the length of the match is irrelevant.

    Array Element Assignment

A subscript may be used on the left side of an assignment like so:

name[exp]=value

In this form of assignment the element or range specified by exp is replaced by the expression on the right side. An array (but not an associative array) may be created by assignment to a range or element. Arrays do not nest, so assigning a parenthesized list of values to an element or range changes the number of elements in the array, shifting the other elements to accommodate the new values. (This is not supported for associative arrays.)

This syntax also works as an argument to the typeset command:

typeset "name[exp]"=value

The value may not be a parenthesized list in this case; only single-element assignments may be made with typeset. Note that quotes are necessary in this case to prevent the brackets from being interpreted as filename generation operators. The noglob precommand modifier could be used instead.

To delete an element of an ordinary array, assign ‘()’ to that element. To delete an element of an associative array, use the unset command:

unset "name[exp]"

    Subscript Flags

If the opening bracket, or the comma in a range, in any subscript expression is directly followed by an opening parenthesis, the string up to the matching closing one is considered to be a list of flags, as in ‘name[(flags)exp]’.

The flags s, n and b take an argument; the delimiter is shown below as ‘:’, but any character, or the matching pairs ‘(...)’, ‘{...}’, ‘[...]’, or ‘<...>’, may be used, but note that ‘<...>’ can only be used if the subscript is inside a double quoted expression or a parameter substitution enclosed in braces as otherwise the expression is interpreted as a redirection.

The flags currently understood are:

w If the parameter subscripted is a scalar then this flag makes subscripting work on words instead of characters. The default word separator is whitespace. This flag may not be used with the i or I flag.
s:string:
  This gives the string that separates words (for use with the w flag). The delimiter character : is arbitrary; see above.
p Recognize the same escape sequences as the print builtin in the string argument of a subsequent ‘s’ flag.
f If the parameter subscripted is a scalar then this flag makes subscripting work on lines instead of characters, i.e. with elements separated by newlines. This is a shorthand for ‘pws:\n:’.
r Reverse subscripting: if this flag is given, the exp is taken as a pattern and the result is the first matching array element, substring or word (if the parameter is an array, if it is a scalar, or if it is a scalar and the ‘w’ flag is given, respectively). The subscript used is the number of the matching element, so that pairs of subscripts such as ‘$foo[(r)??,3]’ and ‘$foo[(r)??,(r)f*]’ are possible if the parameter is not an associative array. If the parameter is an associative array, only the value part of each pair is compared to the pattern, and the result is that value.

If a search through an ordinary array failed, the search sets the subscript to one past the end of the array, and hence ${array[(r)pattern]} will substitute the empty string. Thus the success of a search can be tested by using the (i) flag, for example (assuming the option KSH_ARRAYS is not in effect):

 
[[ ${array[(i)pattern]} -le ${#array} ]]

If KSH_ARRAYS is in effect, the -le should be replaced by -lt.

R Like ‘r’, but gives the last match. For associative arrays, gives all possible matches. May be used for assigning to ordinary array elements, but not for assigning to associative arrays. On failure, for normal arrays this has the effect of returning the element corresponding to subscript 0; this is empty unless one of the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in effect.

Note that in subscripts with both ‘r’ and ‘R’ pattern characters are active even if they were substituted for a parameter (regardless of the setting of GLOB_SUBST which controls this feature in normal pattern matching). The flag ‘e’ can be added to inhibit pattern matching. As this flag does not inhibit other forms of substitution, care is still required; using a parameter to hold the key has the desired effect:

 
key2=’original key’
print ${array[(Re)$key2]}

i Like ‘r’, but gives the index of the match instead; this may not be combined with a second argument. On the left side of an assignment, behaves like ‘r’. For associative arrays, the key part of each pair is compared to the pattern, and the first matching key found is the result. On failure substitutes the length of the array plus one, as discussed under the description of ‘r’, or the empty string for an associative array.
I Like ‘i’, but gives the index of the last match, or all possible matching keys in an associative array. On failure substitutes 0, or the empty string for an associative array. This flag is best when testing for values or keys that do not exist.
k If used in a subscript on an associative array, this flag causes the keys to be interpreted as patterns, and returns the value for the first key found where exp is matched by the key. Note this could be any such key as no ordering of associative arrays is defined. This flag does not work on the left side of an assignment to an associative array element. If used on another type of parameter, this behaves like ‘r’.
K On an associative array this is like ‘k’ but returns all values where exp is matched by the keys. On other types of parameters this has the same effect as ‘R’.
n:expr: If combined with ‘r’, ‘R’, ‘i’ or ‘I’, makes them give the nth or nth last match (if expr evaluates to n). This flag is ignored when the array is associative. The delimiter character : is arbitrary; see above.
b:expr: If combined with ‘r’, ‘R’, ‘i’ or ‘I’, makes them begin at the nth or nth last element, word, or character (if expr evaluates to n). This flag is ignored when the array is associative. The delimiter character : is arbitrary; see above.
e This flag causes any pattern matching that would be performed on the subscript to use plain string matching instead. Hence ‘${array[(re)*]}’ matches only the array element whose value is *. Note that other forms of substitution such as parameter substitution are not inhibited.

This flag can also be used to force * or @ to be interpreted as a single key rather than as a reference to all values. It may be used for either purpose on the left side of an assignment.

See Parameter Expansion Flags (zshexpn(1)) for additional ways to manipulate the results of array subscripting.

    Subscript Parsing

This discussion applies mainly to associative array key strings and to patterns used for reverse subscripting (the ‘r’, ‘R’, ‘i’, etc. flags), but it may also affect parameter substitutions that appear as part of an arithmetic expression in an ordinary subscript.

To avoid subscript parsing limitations in assignments to associative array elements, use the append syntax:

aa+=(’key with "*strange*" characters’ ’value string’)

The basic rule to remember when writing a subscript expression is that all text between the opening ‘[’ and the closing ‘]’ is interpreted as if it were in double quotes (see zshmisc(1)). However, unlike double quotes which normally cannot nest, subscript expressions may appear inside double-quoted strings or inside other subscript expressions (or both!), so the rules have two important differences.

The first difference is that brackets (‘[’ and ‘]’) must appear as balanced pairs in a subscript expression unless they are preceded by a backslash (‘\’). Therefore, within a subscript expression (and unlike true double-quoting) the sequence ‘\[’ becomes ‘[’, and similarly ‘\]’ becomes ‘]’. This applies even in cases where a backslash is not normally required; for example, the pattern ‘[^[]’ (to match any character other than an open bracket) should be written ‘[^\[]’ in a reverse-subscript pattern. However, note that ‘\[^\[\]’ and even ‘\[^[]’ mean the same thing, because backslashes are always stripped when they appear before brackets!

The same rule applies to parentheses (‘(’ and ‘)’) and braces (‘{’ and ‘}’): they must appear either in balanced pairs or preceded by a backslash, and backslashes that protect parentheses or braces are removed during parsing. This is because parameter expansions may be surrounded by balanced braces, and subscript flags are introduced by balanced parentheses.

The second difference is that a double-quote (‘"’) may appear as part of a subscript expression without being preceded by a backslash, and therefore that the two characters ‘\"’ remain as two characters in the subscript (in true double-quoting, ‘\"’ becomes ‘"’). However, because of the standard shell quoting rules, any double-quotes that appear must occur in balanced pairs unless preceded by a backslash. This makes it more difficult to write a subscript expression that contains an odd number of double-quote characters, but the reason for this difference is so that when a subscript expression appears inside true double-quotes, one can still write ‘\"’ (rather than ‘\\\"’) for ‘"’.

To use an odd number of double quotes as a key in an assignment, use the typeset builtin and an enclosing pair of double quotes; to refer to the value of that key, again use double quotes:

typeset -A aa
typeset "aa[one\"two\"three\"quotes]"=QQQ
print "$aa[one\"two\"three\"quotes]"

It is important to note that the quoting rules do not change when a parameter expansion with a subscript is nested inside another subscript expression. That is, it is not necessary to use additional backslashes within the inner subscript expression; they are removed only once, from the innermost subscript outwards. Parameters are also expanded from the innermost subscript first, as each expansion is encountered left to right in the outer expression.

A further complication arises from a way in which subscript parsing is not different from double quote parsing. As in true double-quoting, the sequences ‘\*’, and ‘\@’ remain as two characters when they appear in a subscript expression. To use a literal ‘*’ or ‘@’ as an associative array key, the ‘e’ flag must be used:

typeset -A aa
aa[(e)*]=star
print $aa[(e)*]

A last detail must be considered when reverse subscripting is performed. Parameters appearing in the subscript expression are first expanded and then the complete expression is interpreted as a pattern. This has two effects: first, parameters behave as if GLOB_SUBST were on (and it cannot be turned off); second, backslashes are interpreted twice, once when parsing the array subscript and again when parsing the pattern. In a reverse subscript, it’s necessary to use four backslashes to cause a single backslash to match literally in the pattern. For complex patterns, it is often easiest to assign the desired pattern to a parameter and then refer to that parameter in the subscript, because then the backslashes, brackets, parentheses, etc., are seen only when the complete expression is converted to a pattern. To match the value of a parameter literally in a reverse subscript, rather than as a pattern, use ‘${(q)name}’ (see zshexpn(1)) to quote the expanded value.

Note that the ‘k’ and ‘K’ flags are reverse subscripting for an ordinary array, but are not reverse subscripting for an associative array! (For an associative array, the keys in the array itself are interpreted as patterns by those flags; the subscript is a plain string in that case.)

One final note, not directly related to subscripting: the numeric names of positional parameters (described below) are parsed specially, so for example ‘$2foo’ is equivalent to ‘${2}foo’. Therefore, to use subscript syntax to extract a substring from a positional parameter, the expansion must be surrounded by braces; for example, ‘${2[3,5]}’ evaluates to the third through fifth characters of the second positional parameter, but ‘$2[3,5]’ is the entire second parameter concatenated with the filename generation pattern ‘[3,5]’.

POSITIONAL PARAMETERS

The positional parameters provide access to the command-line arguments of a shell function, shell script, or the shell itself; see the section ‘Invocation’, and also the section ‘Functions’. The parameter n, where n is a number, is the nth positional parameter. The parameter ‘$0’ is a special case, see the section ‘Parameters Set By The Shell’.

The parameters *, @ and argv are arrays containing all the positional parameters; thus ‘$argv[n]’, etc., is equivalent to simply ‘$n’. Note that the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT apply to these arrays as well, so with either of those options set, ‘${argv[0]}’ is equivalent to ‘$1’ and so on.

Positional parameters may be changed after the shell or function starts by using the set builtin, by assigning to the argv array, or by direct assignment of the form ‘n=value’ where n is the number of the positional parameter to be changed. This also creates (with empty values) any of the positions from 1 to n that do not already have values. Note that, because the positional parameters form an array, an array assignment of the form ‘n=(value ...)’ is allowed, and has the effect of shifting all the values at positions greater than n by as many positions as necessary to accommodate the new values.

LOCAL PARAMETERS

Shell function executions delimit scopes for shell parameters. (Parameters are dynamically scoped.) The typeset builtin, and its alternative forms declare, integer, local and readonly (but not export), can be used to declare a parameter as being local to the innermost scope.

When a parameter is read or assigned to, the innermost existing parameter of that name is used. (That is, the local parameter hides any less-local parameter.) However, assigning to a non-existent parameter, or declaring a new parameter with export, causes it to be created in the outermost scope.

Local parameters disappear when their scope ends. unset can be used to delete a parameter while it is still in scope; any outer parameter of the same name remains hidden.

Special parameters may also be made local; they retain their special attributes unless either the existing or the newly-created parameter has the -h (hide) attribute. This may have unexpected effects: there is no default value, so if there is no assignment at the point the variable is made local, it will be set to an empty value (or zero in the case of integers). The following:

typeset PATH=/new/directory:$PATH

is valid for temporarily allowing the shell or programmes called from it to find the programs in /new/directory inside a function.

Note that the restriction in older versions of zsh that local parameters were never exported has been removed.

PARAMETERS SET BY THE SHELL

In the parameter lists that follow, the mark ‘<S>’ indicates that the parameter is special. ‘<Z>’ indicates that the parameter does not exist when the shell initializes in sh or ksh emulation mode.

The following parameters are automatically set by the shell:

! <S> The process ID of the last command started in the background with &, or put into the background with the bg builtin.
# <S> The number of positional parameters in decimal. Note that some confusion may occur with the syntax $#param which substitutes the length of param. Use ${#} to resolve ambiguities. In particular, the sequence ‘$#-...’ in an arithmetic expression is interpreted as the length of the parameter -, q.v.
ARGC <S> <Z> Same as #.
$ <S> The process ID of this shell. Note that this indicates the original shell started by invoking zsh; all processes forked from the shells without executing a new program, such as subshells started by (...), substitute the same value.
- <S> Flags supplied to the shell on invocation or by the set or setopt commands.
* <S> An array containing the positional parameters.
argv <S> <Z> Same as *. Assigning to argv changes the local positional parameters, but argv is not itself a local parameter. Deleting argv with unset in any function deletes it everywhere, although only the innermost positional parameter array is deleted (so * and @ in other scopes are not affected).
@ <S> Same as argv[@], even when argv is not set.
? <S> The exit status returned by the last command.
0 <S> The name used to invoke the current shell, or as set by the -c command line option upon invocation. If the FUNCTION_ARGZERO option is set, $0 is set upon entry to a shell function to the name of the function, and upon entry to a sourced script to the name of the script, and reset to its previous value when the function or script returns.
status <S> <Z>
  Same as ?.
pipestatus <S> <Z>
  An array containing the exit statuses returned by all commands in the last pipeline.
_ <S> The last argument of the previous command. Also, this parameter is set in the environment of every command executed to the full pathname of the command.
CPUTYPE
  The machine type (microprocessor class or machine model), as determined at run time.
EGID <S> The effective group ID of the shell process. If you have sufficient privileges, you may change the effective group ID of the shell process by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command with a different effective group ID by ‘(EGID=gid; command)

If this is made local, it is not implicitly set to 0, but may be explicitly set locally.

EUID <S> The effective user ID of the shell process. If you have sufficient privileges, you may change the effective user ID of the shell process by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command with a different effective user ID by ‘(EUID=uid; command)

If this is made local, it is not implicitly set to 0, but may be explicitly set locally.

ERRNO <S> The value of errno (see errno(3)) as set by the most recently failed system call. This value is system dependent and is intended for debugging purposes. It is also useful with the zsh/system module which allows the number to be turned into a name or message.
GID <S> The real group ID of the shell process. If you have sufficient privileges, you may change the group ID of the shell process by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command under a different group ID by ‘(GID=gid; command)

If this is made local, it is not implicitly set to 0, but may be explicitly set locally.

HISTCMD
  The current history event number in an interactive shell, in other words the event number for the command that caused $HISTCMD to be read. If the current history event modifies the history, HISTCMD changes to the new maximum history event number.
HOST The current hostname.
LINENO <S>
  The line number of the current line within the current script, sourced file, or shell function being executed, whichever was started most recently. Note that in the case of shell functions the line number refers to the function as it appeared in the original definition, not necessarily as displayed by the functions builtin.
LOGNAME
  If the corresponding variable is not set in the environment of the shell, it is initialized to the login name corresponding to the current login session. This parameter is exported by default but this can be disabled using the typeset builtin. The value is set to the string returned by the getlogin(3) system call if that is available.
MACHTYPE
  The machine type (microprocessor class or machine model), as determined at compile time.
OLDPWD The previous working directory. This is set when the shell initializes and whenever the directory changes.
OPTARG <S>
  The value of the last option argument processed by the getopts command.
OPTIND <S>
  The index of the last option argument processed by the getopts command.
OSTYPE The operating system, as determined at compile time.
PPID <S> The process ID of the parent of the shell. As for $$, the value indicates the parent of the original shell and does not change in subshells.
PWD The present working directory. This is set when the shell initializes and whenever the directory changes.
RANDOM <S>
  A pseudo-random integer from 0 to 32767, newly generated each time this parameter is referenced. The random number generator can be seeded by assigning a numeric value to RANDOM.

The values of RANDOM form an intentionally-repeatable pseudo-random sequence; subshells that reference RANDOM will result in identical pseudo-random values unless the value of RANDOM is referenced or seeded in the parent shell in between subshell invocations.

SECONDS <S>
  The number of seconds since shell invocation. If this parameter is assigned a value, then the value returned upon reference will be the value that was assigned plus the number of seconds since the assignment.

Unlike other special parameters, the type of the SECONDS parameter can be changed using the typeset command. Only integer and one of the floating point types are allowed. For example, ‘typeset -F SECONDS’ causes the value to be reported as a floating point number. The value is available to microsecond accuracy, although the shell may show more or fewer digits depending on the use of typeset. See the documentation for the builtin typeset in zshbuiltins(1) for more details.

SHLVL <S> Incremented by one each time a new shell is started.
signals
  An array containing the names of the signals. Note that with the standard zsh numbering of array indices, where the first element has index 1, the signals are offset by 1 from the signal number used by the operating system. For example, on typical Unix-like systems HUP is signal number 1, but is referred to as $signals[2]. This is because of EXIT at position 1 in the array, which is used internally by zsh but is not known to the operating system.
TRY_BLOCK_ERROR <S>
  In an always block, indicates whether the preceding list of code caused an error. The value is 1 to indicate an error, 0 otherwise. It may be reset, clearing the error condition. See Complex Commands in zshmisc(1)
TRY_BLOCK_INTERRUPT <S>
  This variable works in a similar way to TRY_BLOCK_ERROR, but represents the status of an interrupt from the signal SIGINT, which typically comes from the keyboard when the user types ^C. If set to 0, any such interrupt will be reset; otherwise, the interrupt is propagated after the always block.

Note that it is possible that an interrupt arrives during the execution of the always block; this interrupt is also propagated.

TTY The name of the tty associated with the shell, if any.
TTYIDLE <S>
  The idle time of the tty associated with the shell in seconds or -1 if there is no such tty.
UID <S> The real user ID of the shell process. If you have sufficient privileges, you may change the user ID of the shell by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command under a different user ID by ‘(UID=uid; command)

If this is made local, it is not implicitly set to 0, but may be explicitly set locally.

USERNAME <S>
  The username corresponding to the real user ID of the shell process. If you have sufficient privileges, you may change the username (and also the user ID and group ID) of the shell by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command under a different username (and user ID and group ID) by ‘(USERNAME=username; command)
VENDOR The vendor, as determined at compile time.
zsh_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
  An array (colon-separated list) indicating the context of shell code that is being run. Each time a piece of shell code that is stored within the shell is executed a string is temporarily appended to the array to indicate the type of operation that is being performed. Read in order the array gives an indication of the stack of operations being performed with the most immediate context last.

Note that the variable does not give information on syntactic context such as pipelines or subshells. Use $ZSH_SUBSHELL to detect subshells.

The context is one of the following:
cmdarg Code specified by the -c option to the command line that invoked the shell.
cmdsubst
  Command substitution using the ... or $(...) construct.
equalsubst
  File substitution using the =(...) construct.
eval Code executed by the eval builtin.
evalautofunc
  Code executed with the KSH_AUTOLOAD mechanism in order to define an autoloaded function.
fc Code from the shell history executed by the -e option to the fc builtin.
file Lines of code being read directly from a file, for example by the source builtin.
filecode
  Lines of code being read from a .zwc file instead of directly from the source file.
globqual
  Code executed by the e or + glob qualifier.
globsort
  Code executed to order files by the o glob qualifier.
insubst
  File substitution using the <(...) construct.
loadautofunc
  Code read directly from a file to define an autoloaded function.
outsubst
  File substitution using the >(...) construct.
sched Code executed by the sched builtin.
shfunc A shell function.
stty Code passed to stty by the STTY environment variable. Normally this is passed directly to the system’s stty command, so this value is unlikely to be seen in practice.
style Code executed as part of a style retrieved by the zstyle builtin from the zsh/zutil module.
toplevel
  The highest execution level of a script or interactive shell.
trap Code executed as a trap defined by the trap builtin. Traps defined as functions have the context shfunc. As traps are asynchronous they may have a different hierarchy from other code.
zpty Code executed by the zpty builtin from the zsh/zpty module.
zregexparse-guard
  Code executed as a guard by the zregexparse command from the zsh/zutil module.
zregexparse-action
  Code executed as an action by the zregexparse command from the zsh/zutil module.

ZSH_NAME
  Expands to the basename of the command used to invoke this instance of zsh.
ZSH_PATCHLEVEL
  The revision string for the version number of the ChangeLog file in the zsh distribution. This is most useful in order to keep track of versions of the shell during development between releases; hence most users should not use it and should instead rely on $ZSH_VERSION.
zsh_scheduled_events
  See the section ‘The zsh/sched Module’ in zshmodules(1).
ZSH_SUBSHELL
  Readonly integer. Initially zero, incremented each time the shell forks to create a subshell for executing code. Hence ‘(print $ZSH_SUBSHELL)’ and ‘print $(print $ZSH_SUBSHELL)’ output 1, while ‘( (print $ZSH_SUBSHELL) )’ outputs 2.
ZSH_VERSION
  The version number of the release of zsh.

PARAMETERS USED BY THE SHELL

The following parameters are used by the shell. Again, ‘<S>’ indicates that the parameter is special and ‘<Z>’ indicates that the parameter does not exist when the shell initializes in sh or ksh emulation mode.

In cases where there are two parameters with an upper- and lowercase form of the same name, such as path and PATH, the lowercase form is an array and the uppercase form is a scalar with the elements of the array joined together by colons. These are similar to tied parameters created via ‘typeset -T’. The normal use for the colon-separated form is for exporting to the environment, while the array form is easier to manipulate within the shell. Note that unsetting either of the pair will unset the other; they retain their special properties when recreated, and recreating one of the pair will recreate the other.

ARGV0 If exported, its value is used as the argv[0] of external commands. Usually used in constructs like ‘ARGV0=emacs nethack’.
BAUD The rate in bits per second at which data reaches the terminal. The line editor will use this value in order to compensate for a slow terminal by delaying updates to the display until necessary. If the parameter is unset or the value is zero the compensation mechanism is turned off. The parameter is not set by default.

This parameter may be profitably set in some circumstances, e.g. for slow modems dialing into a communications server, or on a slow wide area network. It should be set to the baud rate of the slowest part of the link for best performance.

cdpath <S> <Z> (CDPATH <S>)
  An array (colon-separated list) of directories specifying the search path for the cd command.
COLUMNS <S>
  The number of columns for this terminal session. Used for printing select lists and for the line editor.
CORRECT_IGNORE
  If set, is treated as a pattern during spelling correction. Any potential correction that matches the pattern is ignored. For example, if the value is ‘_*’ then completion functions (which, by convention, have names beginning with ‘_’) will never be offered as spelling corrections. The pattern does not apply to the correction of file names, as applied by the CORRECT_ALL option (so with the example just given files beginning with ‘_’ in the current directory would still be completed).
CORRECT_IGNORE_FILE
  If set, is treated as a pattern during spelling correction of file names. Any file name that matches the pattern is never offered as a correction. For example, if the value is ‘.*’ then dot file names will never be offered as spelling corrections. This is useful with the CORRECT_ALL option.
DIRSTACKSIZE
  The maximum size of the directory stack, by default there is no limit. If the stack gets larger than this, it will be truncated automatically. This is useful with the AUTO_PUSHD option.
ENV If the ENV environment variable is set when zsh is invoked as sh or ksh, $ENV is sourced after the profile scripts. The value of ENV is subjected to parameter expansion, command substitution, and arithmetic expansion before being interpreted as a pathname. Note that ENV is not used unless zsh is emulating sh or ksh.
FCEDIT The default editor for the fc builtin. If FCEDIT is not set, the parameter EDITOR is used; if that is not set either, a builtin default, usually vi, is used.
fignore <S> <Z> (FIGNORE <S>)
  An array (colon separated list) containing the suffixes of files to be ignored during filename completion. However, if completion only generates files with suffixes in this list, then these files are completed anyway.
fpath <S> <Z> (FPATH <S>)
  An array (colon separated list) of directories specifying the search path for function definitions. This path is searched when a function with the -u attribute is referenced. If an executable file is found, then it is read and executed in the current environment.
histchars <S>
  Three characters used by the shell’s history and lexical analysis mechanism. The first character signals the start of a history expansion (default ‘!’). The second character signals the start of a quick history substitution (default ‘^’). The third character is the comment character (default ‘#’).

The characters must be in the ASCII character set; any attempt to set histchars to characters with a locale-dependent meaning will be rejected with an error message.

HISTCHARS <S> <Z>
  Same as histchars. (Deprecated.)
HISTFILE
  The file to save the history in when an interactive shell exits. If unset, the history is not saved.
HISTORY_IGNORE
  If set, is treated as a pattern at the time history files are written. Any potential history entry that matches the pattern is skipped. For example, if the value is ‘fc *’ then commands that invoke the interactive history editor are never written to the history file.

Note that HISTORY_IGNORE defines a single pattern: to specify alternatives use the ‘(first|second|...)’ syntax.

Compare the HIST_NO_STORE option or the zshaddhistory hook, either of which would prevent such commands from being added to the interactive history at all. If you wish to use HISTORY_IGNORE to stop history being added in the first place, you can define the following hook:

 
zshaddhistory() {
  emulate -L zsh
  ## uncomment if HISTORY_IGNORE
  ## should use EXTENDED_GLOB syntax
  # setopt extendedglob
  [[ $1 != ${~HISTORY_IGNORE} ]]
}

HISTSIZE <S>
  The maximum number of events stored in the internal history list. If you use the HIST_EXPIRE_DUPS_FIRST option, setting this value larger than the SAVEHIST size will give you the difference as a cushion for saving duplicated history events.

If this is made local, it is not implicitly set to 0, but may be explicitly set locally.

HOME <S> The default argument for the cd command. This is not set automatically by the shell in sh, ksh or csh emulation, but it is typically present in the environment anyway, and if it becomes set it has its usual special behaviour.
IFS <S> Internal field separators (by default space, tab, newline and NUL), that are used to separate words which result from command or parameter expansion and words read by the read builtin. Any characters from the set space, tab and newline that appear in the IFS are called IFS white space. One or more IFS white space characters or one non-IFS white space character together with any adjacent IFS white space character delimit a field. If an IFS white space character appears twice consecutively in the IFS, this character is treated as if it were not an IFS white space character.

If the parameter is unset, the default is used. Note this has a different effect from setting the parameter to an empty string.

KEYBOARD_HACK
  This variable defines a character to be removed from the end of the command line before interpreting it (interactive shells only). It is intended to fix the problem with keys placed annoyingly close to return and replaces the SUNKEYBOARDHACK option which did this for backquotes only. Should the chosen character be one of singlequote, doublequote or backquote, there must also be an odd number of them on the command line for the last one to be removed.

For backward compatibility, if the SUNKEYBOARDHACK option is explicitly set, the value of KEYBOARD_HACK reverts to backquote. If the option is explicitly unset, this variable is set to empty.

KEYTIMEOUT
  The time the shell waits, in hundredths of seconds, for another key to be pressed when reading bound multi-character sequences.
LANG <S> This variable determines the locale category for any category not specifically selected via a variable starting with ‘LC_’.
LC_ALL <S>
  This variable overrides the value of the ‘LANG’ variable and the value of any of the other variables starting with ‘LC_’.
LC_COLLATE <S>
  This variable determines the locale category for character collation information within ranges in glob brackets and for sorting.
LC_CTYPE <S>
  This variable determines the locale category for character handling functions. If the MULTIBYTE option is in effect this variable or LANG should contain a value that reflects the character set in use, even if it is a single-byte character set, unless only the 7-bit subset (ASCII) is used. For example, if the character set is ISO-8859-1, a suitable value might be en_US.iso88591 (certain Linux distributions) or en_US.ISO8859-1 (MacOS).
LC_MESSAGES <S>
  This variable determines the language in which messages should be written. Note that zsh does not use message catalogs.
LC_NUMERIC <S>
  This variable affects the decimal point character and thousands separator character for the formatted input/output functions and string conversion functions. Note that zsh ignores this setting when parsing floating point mathematical expressions.
LC_TIME <S>
  This variable determines the locale category for date and time formatting in prompt escape sequences.
LINES <S> The number of lines for this terminal session. Used for printing select lists and for the line editor.
LISTMAX
  In the line editor, the number of matches to list without asking first. If the value is negative, the list will be shown if it spans at most as many lines as given by the absolute value. If set to zero, the shell asks only if the top of the listing would scroll off the screen.
LOGCHECK
  The interval in seconds between checks for login/logout activity using the watch parameter.
MAIL If this parameter is set and mailpath is not set, the shell looks for mail in the specified file.
MAILCHECK
  The interval in seconds between checks for new mail.
mailpath <S> <Z> (MAILPATH <S>)
  An array (colon-separated list) of filenames to check for new mail. Each filename can be followed by a ‘?’ and a message that will be printed. The message will undergo parameter expansion, command substitution and arithmetic expansion with the variable $_ defined as the name of the file that has changed. The default message is ‘You have new mail’. If an element is a directory instead of a file the shell will recursively check every file in every subdirectory of the element.
manpath <S> <Z> (MANPATH <S> <Z>)
  An array (colon-separated list) whose value is not used by the shell. The manpath array can be useful, however, since setting it also sets MANPATH, and vice versa.
match
mbegin
mend
Arrays set by the shell when the b globbing flag is used in pattern matches. See the subsection Globbing flags in the documentation for Filename Generation in zshexpn(1).
MATCH
MBEGIN
MEND
Set by the shell when the m globbing flag is used in pattern matches. See the subsection Globbing flags in the documentation for Filename Generation in zshexpn(1).
module_path <S> <Z> (MODULE_PATH <S>)
  An array (colon-separated list) of directories that zmodload searches for dynamically loadable modules. This is initialized to a standard pathname, usually ‘/usr/local/lib/zsh/$ZSH_VERSION’. (The ‘/usr/local/lib’ part varies from installation to installation.) For security reasons, any value set in the environment when the shell is started will be ignored.

These parameters only exist if the installation supports dynamic module loading.

NULLCMD <S>
  The command name to assume if a redirection is specified with no command. Defaults to cat. For sh/ksh behavior, change this to :. For csh-like behavior, unset this parameter; the shell will print an error message if null commands are entered.
path <S> <Z> (PATH <S>)
  An array (colon-separated list) of directories to search for commands. When this parameter is set, each directory is scanned and all files found are put in a hash table.
POSTEDIT <S>
  This string is output whenever the line editor exits. It usually contains termcap strings to reset the terminal.
PROMPT <S> <Z>
PROMPT2 <S> <Z>
PROMPT3 <S> <Z>
PROMPT4 <S> <Z>
  Same as PS1, PS2, PS3 and PS4, respectively.
prompt <S> <Z>
  Same as PS1.
PROMPT_EOL_MARK
  When the PROMPT_CR and PROMPT_SP options are set, the PROMPT_EOL_MARK parameter can be used to customize how the end of partial lines are shown. This parameter undergoes prompt expansion, with the PROMPT_PERCENT option set. If not set, the default behavior is equivalent to the value ‘%B%S%#%s%b’.
PS1 <S> The primary prompt string, printed before a command is read. It undergoes a special form of expansion before being displayed; see EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The default is ‘%m%# ’.
PS2 <S> The secondary prompt, printed when the shell needs more information to complete a command. It is expanded in the same way as PS1. The default is ‘%_> ’, which displays any shell constructs or quotation marks which are currently being processed.
PS3 <S> Selection prompt used within a select loop. It is expanded in the same way as PS1. The default is ‘?# ’.
PS4 <S> The execution trace prompt. Default is ‘+%N:%i> ’, which displays the name of the current shell structure and the line number within it. In sh or ksh emulation, the default is ‘+ ’.
psvar <S> <Z> (PSVAR <S>)
  An array (colon-separated list) whose elements can be used in PROMPT strings. Setting psvar also sets PSVAR, and vice versa.
READNULLCMD <S>
  The command name to assume if a single input redirection is specified with no command. Defaults to more.
REPORTTIME
  If nonnegative, commands whose combined user and system execution times (measured in seconds) are greater than this value have timing statistics printed for them. Output is suppressed for commands executed within the line editor, including completion; commands explicitly marked with the time keyword still cause the summary to be printed in this case.
REPLY This parameter is reserved by convention to pass string values between shell scripts and shell builtins in situations where a function call or redirection are impossible or undesirable. The read builtin and the select complex command may set REPLY, and filename generation both sets and examines its value when evaluating certain expressions. Some modules also employ REPLY for similar purposes.
reply As REPLY, but for array values rather than strings.
RPROMPT <S>
RPS1 <S>
  This prompt is displayed on the right-hand side of the screen when the primary prompt is being displayed on the left. This does not work if the SINGLE_LINE_ZLE option is set. It is expanded in the same way as PS1.
RPROMPT2 <S>
RPS2 <S>
  This prompt is displayed on the right-hand side of the screen when the secondary prompt is being displayed on the left. This does not work if the SINGLE_LINE_ZLE option is set. It is expanded in the same way as PS2.
SAVEHIST
  The maximum number of history events to save in the history file.

If this is made local, it is not implicitly set to 0, but may be explicitly set locally.

SPROMPT <S>
  The prompt used for spelling correction. The sequence ‘%R’ expands to the string which presumably needs spelling correction, and ‘%r’ expands to the proposed correction. All other prompt escapes are also allowed.
STTY If this parameter is set in a command’s environment, the shell runs the stty command with the value of this parameter as arguments in order to set up the terminal before executing the command. The modes apply only to the command, and are reset when it finishes or is suspended. If the command is suspended and continued later with the fg or wait builtins it will see the modes specified by STTY, as if it were not suspended. This (intentionally) does not apply if the command is continued via ‘kill -CONT’. STTY is ignored if the command is run in the background, or if it is in the environment of the shell but not explicitly assigned to in the input line. This avoids running stty at every external command by accidentally exporting it. Also note that STTY should not be used for window size specifications; these will not be local to the command.
TERM <S> The type of terminal in use. This is used when looking up termcap sequences. An assignment to TERM causes zsh to re-initialize the terminal, even if the value does not change (e.g., ‘TERM=$TERM’). It is necessary to make such an assignment upon any change to the terminal definition database or terminal type in order for the new settings to take effect.
TERMINFO <S>
  A reference to a compiled description of the terminal, used by the ‘terminfo’ library when the system has it; see terminfo(5). If set, this causes the shell to reinitialise the terminal, making the workaround ‘TERM=$TERM’ unnecessary.
TIMEFMT
  The format of process time reports with the time keyword. The default is ‘%J %U user %S system %P cpu %*E total’. Recognizes the following escape sequences, although not all may be available on all systems, and some that are available may not be useful:

%% A ‘%’.
%U CPU seconds spent in user mode.
%S CPU seconds spent in kernel mode.
%E Elapsed time in seconds.
%P The CPU percentage, computed as 100*(%U+%S)/%E.
%W Number of times the process was swapped.
%X The average amount in (shared) text space used in kilobytes.
%D The average amount in (unshared) data/stack space used in kilobytes.
%K The total space used (%X+%D) in kilobytes.
%M The maximum memory the process had in use at any time in megabytes.
%F The number of major page faults (page needed to be brought from disk).
%R The number of minor page faults.
%I The number of input operations.
%O The number of output operations.
%r The number of socket messages received.
%s The number of socket messages sent.
%k The number of signals received.
%w Number of voluntary context switches (waits).
%c Number of involuntary context switches.
%J The name of this job.
A star may be inserted between the percent sign and flags printing time. This cause the time to be printed in ‘hh:mm:ss.ttt’ format (hours and minutes are only printed if they are not zero).

TMOUT If this parameter is nonzero, the shell will receive an ALRM signal if a command is not entered within the specified number of seconds after issuing a prompt. If there is a trap on SIGALRM, it will be executed and a new alarm is scheduled using the value of the TMOUT parameter after executing the trap. If no trap is set, and the idle time of the terminal is not less than the value of the TMOUT parameter, zsh terminates. Otherwise a new alarm is scheduled to TMOUT seconds after the last keypress.
TMPPREFIX
  A pathname prefix which the shell will use for all temporary files. Note that this should include an initial part for the file name as well as any directory names. The default is ‘/tmp/zsh’.
watch <S> <Z> (WATCH <S>)
  An array (colon-separated list) of login/logout events to report.

If it contains the single word ‘all’, then all login/logout events are reported. If it contains the single word ‘notme’, then all events are reported as with ‘all’ except $USERNAME.

An entry in this list may consist of a username, an ‘@’ followed by a remote hostname, and a ‘%’ followed by a line (tty). Any of these may be a pattern (be sure to quote this during the assignment to watch so that it does not immediately perform file generation); the setting of the EXTENDED_GLOB option is respected. Any or all of these components may be present in an entry; if a login/logout event matches all of them, it is reported.

For example, with the EXTENDED_GLOB option set, the following:

 
watch=(’^(pws|barts)’)

causes reports for activity assoicated with any user other than pws or barts.

WATCHFMT
  The format of login/logout reports if the watch parameter is set. Default is ‘%n has %a %l from %m’. Recognizes the following escape sequences:

%n The name of the user that logged in/out.
%a The observed action, i.e. "logged on" or "logged off".
%l The line (tty) the user is logged in on.
%M The full hostname of the remote host.
%m The hostname up to the first ‘.’. If only the IP address is available or the utmp field contains the name of an X-windows display, the whole name is printed.

NOTE: The ‘%m’ and ‘%M’ escapes will work only if there is a host name field in the utmp on your machine. Otherwise they are treated as ordinary strings.

%S (%s) Start (stop) standout mode.
%U (%u) Start (stop) underline mode.
%B (%b) Start (stop) boldface mode.
%t
%@
The time, in 12-hour, am/pm format.
%T The time, in 24-hour format.
%w The date in ‘day-dd’ format.
%W The date in ‘mm/dd/yy’ format.
%D The date in ‘yy-mm-dd’ format.
%D{string}
  The date formatted as string using the strftime function, with zsh extensions as described by EXPANSION OF PROMPT SEQUENCES in zshmisc(1).
%(x:true-text:false-text)
  Specifies a ternary expression. The character following the x is arbitrary; the same character is used to separate the text for the "true" result from that for the "false" result. Both the separator and the right parenthesis may be escaped with a backslash. Ternary expressions may be nested.

The test character x may be any one of ‘l’, ‘n’, ‘m’ or ‘M’, which indicate a ‘true’ result if the corresponding escape sequence would return a non-empty value; or it may be ‘a’, which indicates a ‘true’ result if the watched user has logged in, or ‘false’ if he has logged out. Other characters evaluate to neither true nor false; the entire expression is omitted in this case.

If the result is ‘true’, then the true-text is formatted according to the rules above and printed, and the false-text is skipped. If ‘false’, the true-text is skipped and the false-text is formatted and printed. Either or both of the branches may be empty, but both separators must be present in any case.

WORDCHARS <S>
  A list of non-alphanumeric characters considered part of a word by the line editor.
ZBEEP If set, this gives a string of characters, which can use all the same codes as the bindkey command as described in the zsh/zle module entry in zshmodules(1), that will be output to the terminal instead of beeping. This may have a visible instead of an audible effect; for example, the string ‘\e[?5h\e[?5l’ on a vt100 or xterm will have the effect of flashing reverse video on and off (if you usually use reverse video, you should use the string ‘\e[?5l\e[?5h’ instead). This takes precedence over the NOBEEP option.
ZDOTDIR
  The directory to search for shell startup files (.zshrc, etc), if not $HOME.
zle_bracketed_paste
  Many terminal emulators have a feature that allows applications to identify when text is pasted into the terminal rather than being typed normally. For ZLE, this means that special characters such as tabs and newlines can be inserted instead of invoking editor commands. Furthermore, pasted text forms a single undo event and if the region is active, pasted text will replace the region.

This two-element array contains the terminal escape sequences for enabling and disabling the feature. These escape sequences are used to enable bracketed paste when ZLE is active and disable it at other times. Unsetting the parameter has the effect of ensuring that bracketed paste remains disabled.

zle_highlight
  An array describing contexts in which ZLE should highlight the input text. See Character Highlighting in zshzle(1).
ZLE_LINE_ABORTED
  This parameter is set by the line editor when an error occurs. It contains the line that was being edited at the point of the error. ‘print -zr -- $ZLE_LINE_ABORTED’ can be used to recover the line. Only the most recent line of this kind is remembered.
ZLE_REMOVE_SUFFIX_CHARS
ZLE SUFFIX_CHARS
  These parameters are used by the line editor. In certain circumstances suffixes (typically space or slash) added by the completion system will be removed automatically, either because the next editing command was not an insertable character, or because the character was marked as requiring the suffix to be removed.

These variables can contain the sets of characters that will cause the suffix to be removed. If ZLE_REMOVE_SUFFIX_CHARS is set, those characters will cause the suffix to be removed; if ZLE SUFFIX_CHARS is set, those characters will cause the suffix to be removed and replaced by a space.

If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is equivalent to:

 
ZLE_REMOVE_SUFFIX_CHARS=$’ \t\n;&|’

If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no characters have this behaviour. ZLE SUFFIX_CHARS takes precedence, so that the following:

 
ZLE SUFFIX_CHARS=$’&|’

causes the characters ‘&’ and ‘|’ to remove the suffix but to replace it with a space.

To illustrate the difference, suppose that the option AUTO_REMOVE_SLASH is in effect and the directory DIR has just been completed, with an appended /, following which the user types ‘&’. The default result is ‘DIR&’. With ZLE_REMOVE_SUFFIX_CHARS set but without including ‘&’ the result is ‘DIR/&’. With ZLE SUFFIX_CHARS set to include ‘&’ the result is ‘DIR &’.

Note that certain completions may provide their own suffix removal or replacement behaviour which overrides the values described here. See the completion system documentation in zshcompsys(1).

ZLE_RPROMPT_INDENT <S>
  If set, used to give the indentation between the right hand side of the right prompt in the line editor as given by RPS1 or RPROMPT and the right hand side of the screen. If not set, the value 1 is used.

Typically this will be used to set the value to 0 so that the prompt appears flush with the right hand side of the screen. This is not the default as many terminals do not handle this correctly, in particular when the prompt appears at the extreme bottom right of the screen. Recent virtual terminals are more likely to handle this case correctly. Some experimentation is necessary.

NAME

zshoptions - zsh options

SPECIFYING OPTIONS

Options are primarily referred to by name. These names are case insensitive and underscores are ignored. For example, ‘allexport’ is equivalent to ‘A__lleXP_ort’.

The sense of an option name may be inverted by preceding it with ‘no’, so ‘setopt No_Beep’ is equivalent to ‘unsetopt beep’. This inversion can only be done once, so ‘nonobeep’ is not a synonym for ‘beep’. Similarly, ‘tify’ is not a synonym for ‘nonotify’ (the inversion of ‘notify’).

Some options also have one or more single letter names. There are two sets of single letter options: one used by default, and another used to emulate sh/ksh (used when the SH_OPTION_LETTERS option is set). The single letter options can be used on the shell command line, or with the set, setopt and unsetopt builtins, as normal Unix options preceded by ‘-’.

The sense of the single letter options may be inverted by using ‘+’ instead of ‘-’. Some of the single letter option names refer to an option being off, in which case the inversion of that name refers to the option being on. For example, ‘+n’ is the short name of ‘exec’, and ‘-n’ is the short name of its inversion, ‘noexec’.

In strings of single letter options supplied to the shell at startup, trailing whitespace will be ignored; for example the string ‘-f ’ will be treated just as ‘-f’, but the string ‘-f i’ is an error. This is because many systems which implement the ‘#!’ mechanism for calling scripts do not strip trailing whitespace.

DESCRIPTION OF OPTIONS

In the following list, options set by default in all emulations are marked <D>; those set by default only in csh, ksh, sh, or zsh emulations are marked <C>, <K>, <S>, <Z> as appropriate. When listing options (by ‘setopt’, ‘unsetopt’, ‘set -o’ or ‘set +o’), those turned on by default appear in the list prefixed with ‘no’. Hence (unless KSH_OPTION_PRINT is set), ‘setopt’ shows all options whose settings are changed from the default.

    Changing Directories

AUTO_CD (-J)
  If a command is issued that can’t be executed as a normal command, and the command is the name of a directory, perform the cd command to that directory. This option is only applicable if the option SHIN_STDIN is set, i.e. if commands are being read from standard input. The option is designed for interactive use; it is recommended that cd be used explicitly in scripts to avoid ambiguity.
AUTO_PUSHD (-N)
  Make cd push the old directory onto the directory stack.
CDABLE_VARS (-T)
  If the argument to a cd command (or an implied cd with the AUTO_CD option set) is not a directory, and does not begin with a slash, try to expand the expression as if it were preceded by a ‘~’ (see the section ‘Filename Expansion’).
CHASE_DOTS
  When changing to a directory containing a path segment ‘..’ which would otherwise be treated as canceling the previous segment in the path (in other words, ‘foo/..’ would be removed from the path, or if ‘..’ is the first part of the path, the last part of the current working directory would be removed), instead resolve the path to the physical directory. This option is overridden by CHASE_LINKS.

For example, suppose /foo/bar is a link to the directory /alt/rod. Without this option set, ‘cd /foo/bar/..’ changes to /foo; with it set, it changes to /alt. The same applies if the current directory is /foo/bar and ‘cd ..’ is used. Note that all other symbolic links in the path will also be resolved.

CHASE_LINKS (-w)
  Resolve symbolic links to their true values when changing directory. This also has the effect of CHASE_DOTS, i.e. a ‘..’ path segment will be treated as referring to the physical parent, even if the preceding path segment is a symbolic link.
POSIX_CD <K> <S>
  Modifies the behaviour of cd, chdir and pushd commands to make them more compatible with the POSIX standard. The behaviour with the option unset is described in the documentation for the cd builtin in zshbuiltins(1). If the option is set, the shell does not test for directories beneath the local directory (‘.’) until after all directories in cdpath have been tested.

Also, if the option is set, the conditions under which the shell prints the new directory after changing to it are modified. It is no longer restricted to interactive shells (although printing of the directory stack with pushd is still limited to interactive shells); and any use of a component of CDPATH, including a ‘.’ but excluding an empty component that is otherwise treated as ‘.’, causes the directory to be printed.

PUSHD_IGNORE_DUPS
  Don’t push multiple copies of the same directory onto the directory stack.
PUSHD_MINUS
  Exchanges the meanings of ‘+’ and ‘-’ when used with a number to specify a directory in the stack.
PUSHD_SILENT (-E)
  Do not print the directory stack after pushd or popd.
PUSHD_TO_HOME (-D)
  Have pushd with no arguments act like ‘pushd $HOME’.

    Completion

ALWAYS_LAST_PROMPT <D>
  If unset, key functions that list completions try to return to the last prompt if given a numeric argument. If set these functions try to return to the last prompt if given no numeric argument.
ALWAYS_TO_END
  If a completion is performed with the cursor within a word, and a full completion is inserted, the cursor is moved to the end of the word. That is, the cursor is moved to the end of the word if either a single match is inserted or menu completion is performed.
AUTO_LIST (-9) <D>
  Automatically list choices on an ambiguous completion.
AUTO_MENU <D>
  Automatically use menu completion after the second consecutive request for completion, for example by pressing the tab key repeatedly. This option is overridden by MENU_COMPLETE.
AUTO_NAME_DIRS
  Any parameter that is set to the absolute name of a directory immediately becomes a name for that directory, that will be used by the ‘%~’ and related prompt sequences, and will be available when completion is performed on a word starting with ‘~’. (Otherwise, the parameter must be used in the form ‘~param’ first.)
AUTO_PARAM_KEYS <D>
  If a parameter name was completed and a following character (normally a space) automatically inserted, and the next character typed is one of those that have to come directly after the name (like ‘}’, ‘:’, etc.), the automatically added character is deleted, so that the character typed comes immediately after the parameter name. Completion in a brace expansion is affected similarly: the added character is a ‘,’, which will be removed if ‘}’ is typed next.
AUTO_PARAM_SLASH <D>
  If a parameter is completed whose content is the name of a directory, then add a trailing slash instead of a space.
AUTO_REMOVE_SLASH <D>
  When the last character resulting from a completion is a slash and the next character typed is a word delimiter, a slash, or a character that ends a command (such as a semicolon or an ampersand), remove the slash.
BASH_AUTO_LIST
  On an ambiguous completion, automatically list choices when the completion function is called twice in succession. This takes precedence over AUTO_LIST. The setting of LIST_AMBIGUOUS is respected. If AUTO_MENU is set, the menu behaviour will then start with the third press. Note that this will not work with MENU_COMPLETE, since repeated completion calls immediately cycle through the list in that case.
COMPLETE_ALIASES
  Prevents aliases on the command line from being internally substituted before completion is attempted. The effect is to make the alias a distinct command for completion purposes.
COMPLETE_IN_WORD
  If unset, the cursor is set to the end of the word if completion is started. Otherwise it stays there and completion is done from both ends.
GLOB_COMPLETE
  When the current word has a glob pattern, do not insert all the words resulting from the expansion but generate matches as for completion and cycle through them like MENU_COMPLETE. The matches are generated as if a ‘*’ was added to the end of the word, or inserted at the cursor when COMPLETE_IN_WORD is set. This actually uses pattern matching, not globbing, so it works not only for files but for any completion, such as options, user names, etc.

Note that when the pattern matcher is used, matching control (for example, case-insensitive or anchored matching) cannot be used. This limitation only applies when the current word contains a pattern; simply turning on the GLOB_COMPLETE option does not have this effect.

HASH_LIST_ALL <D>
  Whenever a command completion or spelling correction is attempted, make sure the entire command path is hashed first. This makes the first completion slower but avoids false reports of spelling errors.
LIST_AMBIGUOUS <D>
  This option works when AUTO_LIST or BASH_AUTO_LIST is also set. If there is an unambiguous prefix to insert on the command line, that is done without a completion list being displayed; in other words, auto-listing behaviour only takes place when nothing would be inserted. In the case of BASH_AUTO_LIST, this means that the list will be delayed to the third call of the function.
LIST_BEEP <D>
  Beep on an ambiguous completion. More accurately, this forces the completion widgets to return status 1 on an ambiguous completion, which causes the shell to beep if the option BEEP is also set; this may be modified if completion is called from a user-defined widget.
LIST_PACKED
  Try to make the completion list smaller (occupying less lines) by printing the matches in columns with different widths.
LIST_ROWS_FIRST
  Lay out the matches in completion lists sorted horizontally, that is, the second match is to the right of the first one, not under it as usual.
LIST_TYPES (-X) <D>
  When listing files that are possible completions, show the type of each file with a trailing identifying mark.
MENU_COMPLETE (-Y)
  On an ambiguous completion, instead of listing possibilities or beeping, insert the first match immediately. Then when completion is requested again, remove the first match and insert the second match, etc. When there are no more matches, go back to the first one again. reverse-menu-complete may be used to loop through the list in the other direction. This option overrides AUTO_MENU.
REC_EXACT (-S)
  In completion, recognize exact matches even if they are ambiguous.

    Expansion and Globbing

BAD_PATTERN (+2) <C> <Z>
  If a pattern for filename generation is badly formed, print an error message. (If this option is unset, the pattern will be left unchanged.)
BARE_GLOB_QUAL <Z>
  In a glob pattern, treat a trailing set of parentheses as a qualifier list, if it contains no ‘|’, ‘(’ or (if special) ‘~’ characters. See the section ‘Filename Generation’.
BRACE_CCL
  Expand expressions in braces which would not otherwise undergo brace expansion to a lexically ordered list of all the characters. See the section ‘Brace Expansion’.
CASE_GLOB <D>
  Make globbing (filename generation) sensitive to case. Note that other uses of patterns are always sensitive to case. If the option is unset, the presence of any character which is special to filename generation will cause case-insensitive matching. For example, cvs(/) can match the directory CVS owing to the presence of the globbing flag (unless the option BARE_GLOB_QUAL is unset).
CASE_MATCH <D>
  Make regular expressions using the zsh/regex module (including matches with =~) sensitive to case.
CSH_NULL_GLOB <C>
  If a pattern for filename generation has no matches, delete the pattern from the argument list; do not report an error unless all the patterns in a command have no matches. Overrides NOMATCH.
EQUALS <Z>
  Perform = filename expansion. (See the section ‘Filename Expansion’.)
EXTENDED_GLOB
  Treat the ‘#’, ‘~’ and ‘^’ characters as part of patterns for filename generation, etc. (An initial unquoted ‘~’ always produces named directory expansion.)
FORCE_FLOAT
  Constants in arithmetic evaluation will be treated as floating point even without the use of a decimal point; the values of integer variables will be converted to floating point when used in arithmetic expressions. Integers in any base will be converted.
GLOB (+F, ksh: +f) <D>
  Perform filename generation (globbing). (See the section ‘Filename Generation’.)
GLOB_ASSIGN <C>
  If this option is set, filename generation (globbing) is performed on the right hand side of scalar parameter assignments of the form ‘name=pattern (e.g. ‘foo=*’). If the result has more than one word the parameter will become an array with those words as arguments. This option is provided for backwards compatibility only: globbing is always performed on the right hand side of array assignments of the form ‘name=(value)’ (e.g. ‘foo=(*)’) and this form is recommended for clarity; with this option set, it is not possible to predict whether the result will be an array or a scalar.
GLOB_DOTS (-4)
  Do not require a leading ‘.’ in a filename to be matched explicitly.
GLOB_STAR_SHORT
  When this option is set and the default zsh-style globbing is in effect, the pattern ‘**/*’ can be abbreviated to ‘**’ and the pattern ‘***/*’ can be abbreviated to ***. Hence ‘**.c’ finds a file ending in .c in any subdirectory, and ‘***.c’ does the same while also following symbolic links. A / immediately after the ‘**’ or ‘***’ forces the pattern to be treated as the unabbreviated form.
GLOB_SUBST <C> <K> <S>
  Treat any characters resulting from parameter expansion as being eligible for filename expansion and filename generation, and any characters resulting from command substitution as being eligible for filename generation. Braces (and commas in between) do not become eligible for expansion.
HIST_SUBST_PATTERN
  Substitutions using the :s and :& history modifiers are performed with pattern matching instead of string matching. This occurs wherever history modifiers are valid, including glob qualifiers and parameters. See the section Modifiers in zshexpn(1).
IGNORE_BRACES (-I) <S>
  Do not perform brace expansion. For historical reasons this also includes the effect of the IGNORE_CLOSE_BRACES option.
IGNORE_CLOSE_BRACES
  When neither this option nor IGNORE_BRACES is set, a sole close brace character ‘}’ is syntactically significant at any point on a command line. This has the effect that no semicolon or newline is necessary before the brace terminating a function or current shell construct. When either option is set, a closing brace is syntactically significant only in command position. Unlike IGNORE_BRACES, this option does not disable brace expansion.

For example, with both options unset a function may be defined in the following fashion:

 
args() { echo $# }

while if either option is set, this does not work and something equivalent to the following is required:

 
args() { echo $#; }

KSH_GLOB <K>
  In pattern matching, the interpretation of parentheses is affected by a preceding ‘@’, ‘*’, ‘+’, ‘?’ or ‘!’. See the section ‘Filename Generation’.
MAGIC_EQUAL_SUBST
  All unquoted arguments of the form ‘anything=expression’ appearing after the command name have filename expansion (that is, where expression has a leading ‘~’ or ‘=’) performed on expression as if it were a parameter assignment. The argument is not otherwise treated specially; it is passed to the command as a single argument, and not used as an actual parameter assignment. For example, in echo foo=~/bar:~/rod, both occurrences of ~ would be replaced. Note that this happens anyway with typeset and similar statements.

This option respects the setting of the KSH_TYPESET option. In other words, if both options are in effect, arguments looking like assignments will not undergo word splitting.

MARK_DIRS (-8, ksh: -X)
  Append a trailing ‘/’ to all directory names resulting from filename generation (globbing).
MULTIBYTE <D>
  Respect multibyte characters when found in strings. When this option is set, strings are examined using the system library to determine how many bytes form a character, depending on the current locale. This affects the way characters are counted in pattern matching, parameter values and various delimiters.

The option is on by default if the shell was compiled with MULTIBYTE_SUPPORT; otherwise it is off by default and has no effect if turned on.

If the option is off a single byte is always treated as a single character. This setting is designed purely for examining strings known to contain raw bytes or other values that may not be characters in the current locale. It is not necessary to unset the option merely because the character set for the current locale does not contain multibyte characters.

The option does not affect the shell’s editor, which always uses the locale to determine multibyte characters. This is because the character set displayed by the terminal emulator is independent of shell settings.

NOMATCH (+3) <C> <Z>
  If a pattern for filename generation has no matches, print an error, instead of leaving it unchanged in the argument list. This also applies to file expansion of an initial ‘~’ or ‘=’.
NULL_GLOB (-G)
  If a pattern for filename generation has no matches, delete the pattern from the argument list instead of reporting an error. Overrides NOMATCH.
NUMERIC_GLOB_SORT
  If numeric filenames are matched by a filename generation pattern, sort the filenames numerically rather than lexicographically.
RC_EXPAND_PARAM (-P)
  Array expansions of the form ‘foo${xx}bar’, where the parameter xx is set to (a b c), are substituted with ‘fooabar foobbar foocbar’ instead of the default ‘fooa b cbar’. Note that an empty array will therefore cause all arguments to be removed.
REMATCH_PCRE <Z>
  If set, regular expression matching with the =~ operator will use Perl-Compatible Regular Expressions from the PCRE library, if available. If not set, regular expressions will use the extended regexp syntax provided by the system libraries.
SH_GLOB <K> <S>
  Disables the special meaning of ‘(’, ‘|’, ‘)’ and ’<’ for globbing the result of parameter and command substitutions, and in some other places where the shell accepts patterns. If SH_GLOB is set but KSH_GLOB is not, the shell allows the interpretation of subshell expressions enclosed in parentheses in some cases where there is no space before the opening parenthesis, e.g. !(true) is interpreted as if there were a space after the !. This option is set by default if zsh is invoked as sh or ksh.
UNSET (+u, ksh: +u) <K> <S> <Z>
  Treat unset parameters as if they were empty when substituting. Otherwise they are treated as an error.
WARN_CREATE_GLOBAL
  Print a warning message when a global parameter is created in a function by an assignment or in math context. This often indicates that a parameter has not been declared local when it should have been. Parameters explicitly declared global from within a function using typeset -g do not cause a warning. Note that there is no warning when a local parameter is assigned to in a nested function, which may also indicate an error.

    History

APPEND_HISTORY <D>
  If this is set, zsh sessions will append their history list to the history file, rather than replace it. Thus, multiple parallel zsh sessions will all have the new entries from their history lists added to the history file, in the order that they exit. The file will still be periodically re-written to trim it when the number of lines grows 20% beyond the value specified by $SAVEHIST (see also the HIST_SAVE_BY_COPY option).
BANG_HIST (+K) <C> <Z>
  Perform textual history expansion, csh-style, treating the character ‘!’ specially.
EXTENDED_HISTORY <C>
  Save each command’s beginning timestamp (in seconds since the epoch) and the duration (in seconds) to the history file. The format of this prefixed data is:

: <beginning time>:<elapsed seconds>;<command>’.

HIST_ALLOW_CLOBBER
  Add ‘|’ to output redirections in the history. This allows history references to clobber files even when CLOBBER is unset.
HIST_BEEP <D>
  Beep in ZLE when a widget attempts to access a history entry which isn’t there.
HIST_EXPIRE_DUPS_FIRST
  If the internal history needs to be trimmed to add the current command line, setting this option will cause the oldest history event that has a duplicate to be lost before losing a unique event from the list. You should be sure to set the value of HISTSIZE to a larger number than SAVEHIST in order to give you some room for the duplicated events, otherwise this option will behave just like HIST_IGNORE_ALL_DUPS once the history fills up with unique events.
HIST_FCNTL_LOCK
  When writing out the history file, by default zsh uses ad-hoc file locking to avoid known problems with locking on some operating systems. With this option locking is done by means of the system’s fcntl call, where this method is available. On recent operating systems this may provide better performance, in particular avoiding history corruption when files are stored on NFS.
HIST_FIND_NO_DUPS
  When searching for history entries in the line editor, do not display duplicates of a line previously found, even if the duplicates are not contiguous.
HIST_IGNORE_ALL_DUPS
  If a new command line being added to the history list duplicates an older one, the older command is removed from the list (even if it is not the previous event).
HIST_IGNORE_DUPS (-h)
  Do not enter command lines into the history list if they are duplicates of the previous event.
HIST_IGNORE_SPACE (-g)
  Remove command lines from the history list when the first character on the line is a space, or when one of the expanded aliases contains a leading space. Only normal aliases (not global or suffix aliases) have this behaviour. Note that the command lingers in the internal history until the next command is entered before it vanishes, allowing you to briefly reuse or edit the line. If you want to make it vanish right away without entering another command, type a space and press return.
HIST_LEX_WORDS
  By default, shell history that is read in from files is split into words on all white space. This means that arguments with quoted whitespace are not correctly handled, with the consequence that references to words in history lines that have been read from a file may be inaccurate. When this option is set, words read in from a history file are divided up in a similar fashion to normal shell command line handling. Although this produces more accurately delimited words, if the size of the history file is large this can be slow. Trial and error is necessary to decide.
HIST_NO_FUNCTIONS
  Remove function definitions from the history list. Note that the function lingers in the internal history until the next command is entered before it vanishes, allowing you to briefly reuse or edit the definition.
HIST_NO_STORE
  Remove the history (fc -l) command from the history list when invoked. Note that the command lingers in the internal history until the next command is entered before it vanishes, allowing you to briefly reuse or edit the line.
HIST_REDUCE_BLANKS
  Remove superfluous blanks from each command line being added to the history list.
HIST_SAVE_BY_COPY <D>
  When the history file is re-written, we normally write out a copy of the file named $HISTFILE.new and then rename it over the old one. However, if this option is unset, we instead truncate the old history file and write out the new version in-place. If one of the history-appending options is enabled, this option only has an effect when the enlarged history file needs to be re-written to trim it down to size. Disable this only if you have special needs, as doing so makes it possible to lose history entries if zsh gets interrupted during the save.

When writing out a copy of the history file, zsh preserves the old file’s permissions and group information, but will refuse to write out a new file if it would change the history file’s owner.

HIST_SAVE_NO_DUPS
  When writing out the history file, older commands that duplicate newer ones are omitted.
HIST_VERIFY
  Whenever the user enters a line with history expansion, don’t execute the line directly; instead, perform history expansion and reload the line into the editing buffer.
INC_APPEND_HISTORY
  This options works like APPEND_HISTORY except that new history lines are added to the $HISTFILE incrementally (as soon as they are entered), rather than waiting until the shell exits. The file will still be periodically re-written to trim it when the number of lines grows 20% beyond the value specified by $SAVEHIST (see also the HIST_SAVE_BY_COPY option).
INC_APPEND_HISTORY_TIME
  This option is a variant of INC_APPEND_HISTORY in which, where possible, the history entry is written out to the file after the command is finished, so that the time taken by the command is recorded correctly in the history file in EXTENDED_HISTORY format. This means that the history entry will not be available immediately from other instances of the shell that are using the same history file.

This option is only useful if INC_APPEND_HISTORY and SHARE_HISTORY are turned off. The three options should be considered mutually exclusive.

SHARE_HISTORY <K>
 

This option both imports new commands from the history file, and also causes your typed commands to be appended to the history file (the latter is like specifying INC_APPEND_HISTORY, which should be turned off if this option is in effect). The history lines are also output with timestamps ala EXTENDED_HISTORY (which makes it easier to find the spot where we left off reading the file after it gets re-written).

By default, history movement commands visit the imported lines as well as the local lines, but you can toggle this on and off with the set-local-history zle binding. It is also possible to create a zle widget that will make some commands ignore imported commands, and some include them.

If you find that you want more control over when commands get imported, you may wish to turn SHARE_HISTORY off, INC_APPEND_HISTORY or INC_APPEND_HISTORY_TIME (see above) on, and then manually import commands whenever you need them using ‘fc -RI’.

    Initialisation

ALL_EXPORT (-a, ksh: -a)
  All parameters subsequently defined are automatically exported.
GLOBAL_EXPORT <Z>
  If this option is set, passing the -x flag to the builtins declare, float, integer, readonly and typeset (but not local) will also set the -g flag; hence parameters exported to the environment will not be made local to the enclosing function, unless they were already or the flag +g is given explicitly. If the option is unset, exported parameters will be made local in just the same way as any other parameter.

This option is set by default for backward compatibility; it is not recommended that its behaviour be relied upon. Note that the builtin export always sets both the -x and -g flags, and hence its effect extends beyond the scope of the enclosing function; this is the most portable way to achieve this behaviour.

GLOBAL_RCS (-d) <D>
  If this option is unset, the startup files /etc/zprofile, /etc/zshrc, /etc/zlogin and /etc/zlogout will not be run. It can be disabled and re-enabled at any time, including inside local startup files (.zshrc, etc.).
RCS (+f) <D>
  After /etc/zshenv is sourced on startup, source the .zshenv, /etc/zprofile, .zprofile, /etc/zshrc, .zshrc, /etc/zlogin, .zlogin, and .zlogout files, as described in the section ‘Files’. If this option is unset, the /etc/zshenv file is still sourced, but any of the others will not be; it can be set at any time to prevent the remaining startup files after the currently executing one from being sourced.

    Input/Output

ALIASES <D>
  Expand aliases.
CLOBBER (+C, ksh: +C) <D>
  Allows ‘>’ redirection to truncate existing files. Otherwise ‘>!’ or ‘>|’ must be used to truncate a file.

If the option is not set, and the option APPEND_CREATE is also not set, ‘>>!’ or ‘>>|’ must be used to create a file. If either option is set, ‘>>’ may be used.

CORRECT (-0)
  Try to correct the spelling of commands. Note that, when the HASH_LIST_ALL option is not set or when some directories in the path are not readable, this may falsely report spelling errors the first time some commands are used.

The shell variable CORRECT_IGNORE may be set to a pattern to match words that will never be offered as corrections.

CORRECT_ALL (-O)
  Try to correct the spelling of all arguments in a line.

The shell variable CORRECT_IGNORE_FILE may be set to a pattern to match file names that will never be offered as corrections.

DVORAK Use the Dvorak keyboard instead of the standard qwerty keyboard as a basis for examining spelling mistakes for the CORRECT and CORRECT_ALL options and the spell-word editor command.
FLOW_CONTROL <D>
  If this option is unset, output flow control via start/stop characters (usually assigned to ^S/^Q) is disabled in the shell’s editor.
IGNORE_EOF (-7)
  Do not exit on end-of-file. Require the use of exit or logout instead. However, ten consecutive EOFs will cause the shell to exit anyway, to avoid the shell hanging if its tty goes away.

Also, if this option is set and the Zsh Line Editor is used, widgets implemented by shell functions can be bound to EOF (normally Control-D) without printing the normal warning message. This works only for normal widgets, not for completion widgets.

INTERACTIVE_COMMENTS (-k) <K> <S>
  Allow comments even in interactive shells.
HASH_CMDS <D>
  Note the location of each command the first time it is executed. Subsequent invocations of the same command will use the saved location, avoiding a path search. If this option is unset, no path hashing is done at all. However, when CORRECT is set, commands whose names do not appear in the functions or aliases hash tables are hashed in order to avoid reporting them as spelling errors.
HASH_DIRS <D>
  Whenever a command name is hashed, hash the directory containing it, as well as all directories that occur earlier in the path. Has no effect if neither HASH_CMDS nor CORRECT is set.
HASH_EXECUTABLES_ONLY
  When hashing commands because of HASH_CMDS, check that the file to be hashed is actually an executable. This option is unset by default as if the path contains a large number of commands, or consists of many remote files, the additional tests can take a long time. Trial and error is needed to show if this option is beneficial.
MAIL_WARNING (-U)
  Print a warning message if a mail file has been accessed since the shell last checked.
PATH_DIRS (-Q)
  Perform a path search even on command names with slashes in them. Thus if ‘/usr/local/bin’ is in the user’s path, and he or she types ‘X11/xinit’, the command ‘/usr/local/bin/X11/xinit’ will be executed (assuming it exists). Commands explicitly beginning with ‘/’, ‘./’ or ‘../’ are not subject to the path search. This also applies to the ‘.’ and source builtins.

Note that subdirectories of the current directory are always searched for executables specified in this form. This takes place before any search indicated by this option, and regardless of whether ‘.’ or the current directory appear in the command search path.

PATH_SCRIPT <K> <S>
  If this option is not set, a script passed as the first non-option argument to the shell must contain the name of the file to open. If this option is set, and the script does not specify a directory path, the script is looked for first in the current directory, then in the command path. See the section INVOCATION in zsh(1).
PRINT_EIGHT_BIT
  Print eight bit characters literally in completion lists, etc. This option is not necessary if your system correctly returns the printability of eight bit characters (see ctype(3)).
PRINT_EXIT_VALUE (-1)
  Print the exit value of programs with non-zero exit status. This is only available at the command line in interactive shells.
RC_QUOTES
  Allow the character sequence ‘’’’ to signify a single quote within singly quoted strings. Note this does not apply in quoted strings using the format $’..., where a backslashed single quote can be used.
RM_STAR_SILENT (-H) <K> <S>
  Do not query the user before executing ‘rm *’ or ‘rm path/*’.
RM_STAR_WAIT
  If querying the user before executing ‘rm *’ or ‘rm path/*’, first wait ten seconds and ignore anything typed in that time. This avoids the problem of reflexively answering ‘yes’ to the query when one didn’t really mean it. The wait and query can always be avoided by expanding the ‘*’ in ZLE (with tab).
SHORT_LOOPS <C> <Z>
  Allow the short forms of for, repeat, select, if, and function constructs.
SUN_KEYBOARD_HACK (-L)
  If a line ends with a backquote, and there are an odd number of backquotes on the line, ignore the trailing backquote. This is useful on some keyboards where the return key is too small, and the backquote key lies annoyingly close to it. As an alternative the variable KEYBOARD_HACK lets you choose the character to be removed.

    Job Control

AUTO_CONTINUE
  With this option set, stopped jobs that are removed from the job table with the disown builtin command are automatically sent a CONT signal to make them running.
AUTO_RESUME (-W)
  Treat single word simple commands without redirection as candidates for resumption of an existing job.
BG_NICE (-6) <C> <Z>
  Run all background jobs at a lower priority. This option is set by default.
CHECK_JOBS <Z>
  Report the status of background and suspended jobs before exiting a shell with job control; a second attempt to exit the shell will succeed. NO_CHECK_JOBS is best used only in combination with NO_HUP, else such jobs will be killed automatically.

The check is omitted if the commands run from the previous command line included a ‘jobs’ command, since it is assumed the user is aware that there are background or suspended jobs. A ‘jobs’ command run from one of the hook functions defined in the section SPECIAL FUNCTIONS in zshmisc(1) is not counted for this purpose.

HUP <Z> Send the HUP signal to running jobs when the shell exits.
LONG_LIST_JOBS (-R)
  List jobs in the long format by default.
MONITOR (-m, ksh: -m)
  Allow job control. Set by default in interactive shells.
NOTIFY (-5, ksh: -b) <Z>
  Report the status of background jobs immediately, rather than waiting until just before printing a prompt.
POSIX_JOBS <K> <S>
  This option makes job control more compliant with the POSIX standard.

When the option is not set, the MONITOR option is unset on entry to subshells, so that job control is no longer active. When the option is set, the MONITOR option and job control remain active in the subshell, but note that the subshell has no access to jobs in the parent shell.

When the option is not set, jobs put in the background or foreground with bg or fg are displayed with the same information that would be reported by jobs. When the option is set, only the text is printed. The output from jobs itself is not affected by the option.

When the option is not set, job information from the parent shell is saved for output within a subshell (for example, within a pipeline). When the option is set, the output of jobs is empty until a job is started within the subshell.

In previous versions of the shell, it was necessary to enable POSIX_JOBS in order for the builtin command wait to return the status of background jobs that had already exited. This is no longer the case.

    Prompting

PROMPT_BANG <K>
  If set, ‘!’ is treated specially in prompt expansion. See EXPANSION OF PROMPT SEQUENCES in zshmisc(1).
PROMPT_CR (+V) <D>
  Print a carriage return just before printing a prompt in the line editor. This is on by default as multi-line editing is only possible if the editor knows where the start of the line appears.
PROMPT_SP <D>
  Attempt to preserve a partial line (i.e. a line that did not end with a newline) that would otherwise be covered up by the command prompt due to the PROMPT_CR option. This works by outputting some cursor-control characters, including a series of spaces, that should make the terminal wrap to the next line when a partial line is present (note that this is only successful if your terminal has automatic margins, which is typical).

When a partial line is preserved, by default you will see an inverse+bold character at the end of the partial line: a ‘%’ for a normal user or a ‘#’ for root. If set, the shell parameter PROMPT_EOL_MARK can be used to customize how the end of partial lines are shown.

NOTE: if the PROMPT_CR option is not set, enabling this option will have no effect. This option is on by default.

PROMPT_PERCENT <C> <Z>
  If set, ‘%’ is treated specially in prompt expansion. See EXPANSION OF PROMPT SEQUENCES in zshmisc(1).
PROMPT_SUBST <K> <S>
  If set, parameter expansion, command substitution and arithmetic expansion are performed in prompts. Substitutions within prompts do not affect the command status.
TRANSIENT_RPROMPT
  Remove any right prompt from display when accepting a command line. This may be useful with terminals with other cut/paste methods.

    Scripts and Functions

C_BASES
  Output hexadecimal numbers in the standard C format, for example ‘0xFF’ instead of the usual ‘16#FF’. If the option OCTAL_ZEROES is also set (it is not by default), octal numbers will be treated similarly and hence appear as ‘077’ instead of ‘8#77’. This option has no effect on the choice of the output base, nor on the output of bases other than hexadecimal and octal. Note that these formats will be understood on input irrespective of the setting of C_BASES.
C_PRECEDENCES
  This alters the precedence of arithmetic operators to be more like C and other programming languages; the section ARITHMETIC EVALUATION in zshmisc(1) has an explicit list.
DEBUG_BEFORE_CMD <D>
  Run the DEBUG trap before each command; otherwise it is run after each command. Setting this option mimics the behaviour of ksh 93; with the option unset the behaviour is that of ksh 88.
ERR_EXIT (-e, ksh: -e)
  If a command has a non-zero exit status, execute the ZERR trap, if set, and exit. This is disabled while running initialization scripts.

The behaviour is also disabled inside DEBUG traps. In this case the option is handled specially: it is unset on entry to the trap. If the option DEBUG_BEFORE_CMD is set, as it is by default, and the option ERR_EXIT is found to have been set on exit, then the command for which the DEBUG trap is being executed is skipped. The option is restored after the trap exits.

Exiting due to ERR_EXIT has certain interactions with asynchronous jobs noted in the section JOBS in in zshmisc(1).

ERR_RETURN
  If a command has a non-zero exit status, return immediately from the enclosing function. The logic is identical to that for ERR_EXIT, except that an implicit return statement is executed instead of an exit. This will trigger an exit at the outermost level of a non-interactive script.
EVAL_LINENO <Z>
  If set, line numbers of expressions evaluated using the builtin eval are tracked separately of the enclosing environment. This applies both to the parameter LINENO and the line number output by the prompt escape %i. If the option is set, the prompt escape %N will output the string ‘(eval)’ instead of the script or function name as an indication. (The two prompt escapes are typically used in the parameter PS4 to be output when the option XTRACE is set.) If EVAL_LINENO is unset, the line number of the surrounding script or function is retained during the evaluation.
EXEC (+n, ksh: +n) <D>
  Do execute commands. Without this option, commands are read and checked for syntax errors, but not executed. This option cannot be turned off in an interactive shell, except when ‘-n’ is supplied to the shell at startup.
FUNCTION_ARGZERO <C> <Z>
  When executing a shell function or sourcing a script, set $0 temporarily to the name of the function/script. Note that toggling FUNCTION_ARGZERO from on to off (or off to on) does not change the current value of $0. Only the state upon entry to the function or script has an effect. Compare POSIX_ARGZERO.
LOCAL_LOOPS
  When this option is not set, the effect of break and continue commands may propagate outside function scope, affecting loops in calling functions. When the option is set in a calling function, a break or a continue that is not caught within a called function (regardless of the setting of the option within that function) produces a warning and the effect is cancelled.
LOCAL_OPTIONS <K>
  If this option is set at the point of return from a shell function, most options (including this one) which were in force upon entry to the function are restored; options that are not restored are PRIVILEGED and RESTRICTED. Otherwise, only this option, and the LOCAL_LOOPS, XTRACE and PRINT_EXIT_VALUE options are restored. Hence if this is explicitly unset by a shell function the other options in force at the point of return will remain so. A shell function can also guarantee itself a known shell configuration with a formulation like ‘emulate -L zsh’; the -L activates LOCAL_OPTIONS.
LOCAL_PATTERNS
  If this option is set at the point of return from a shell function, the state of pattern disables, as set with the builtin command ‘disable -p’, is restored to what it was when the function was entered. The behaviour of this option is similar to the effect of LOCAL_OPTIONS on options; hence ‘emulate -L sh’ (or indeed any other emulation with the -L option) activates LOCAL_PATTERNS.
LOCAL_TRAPS <K>
  If this option is set when a signal trap is set inside a function, then the previous status of the trap for that signal will be restored when the function exits. Note that this option must be set prior to altering the trap behaviour in a function; unlike LOCAL_OPTIONS, the value on exit from the function is irrelevant. However, it does not need to be set before any global trap for that to be correctly restored by a function. For example,

 
unsetopt localtraps
trap - INT
fn() { setopt localtraps; trap ’’ INT; sleep 3; }

will restore normal handling of SIGINT after the function exits.

MULTI_FUNC_DEF <Z>
  Allow definitions of multiple functions at once in the form ‘fn1 fn2...()’; if the option is not set, this causes a parse error. Definition of multiple functions with the function keyword is always allowed. Multiple function definitions are not often used and can cause obscure errors.
MULTIOS <Z>
  Perform implicit tees or cats when multiple redirections are attempted (see the section ‘Redirection’).
OCTAL_ZEROES <S>
  Interpret any integer constant beginning with a 0 as octal, per IEEE Std 1003.2-1992 (ISO 9945-2:1993). This is not enabled by default as it causes problems with parsing of, for example, date and time strings with leading zeroes.

Sequences of digits indicating a numeric base such as the ‘08’ component in ‘08#77’ are always interpreted as decimal, regardless of leading zeroes.

PIPE_FAIL
  By default, when a pipeline exits the exit status recorded by the shell and returned by the shell variable $? reflects that of the rightmost element of a pipeline. If this option is set, the exit status instead reflects the status of the rightmost element of the pipeline that was non-zero, or zero if all elements exited with zero status.
SOURCE_TRACE
  If set, zsh will print an informational message announcing the name of each file it loads. The format of the output is similar to that for the XTRACE option, with the message <sourcetrace>. A file may be loaded by the shell itself when it starts up and shuts down (Startup/Shutdown Files) or by the use of the ‘source’ and ‘dot’ builtin commands.
TYPESET_SILENT
  If this is unset, executing any of the ‘typeset’ family of commands with no options and a list of parameters that have no values to be assigned but already exist will display the value of the parameter. If the option is set, they will only be shown when parameters are selected with the ‘-m’ option. The option ‘-p’ is available whether or not the option is set.
VERBOSE (-v, ksh: -v)
  Print shell input lines as they are read.
XTRACE (-x, ksh: -x)
  Print commands and their arguments as they are executed. The output is preceded by the value of $PS4, formatted as described in the section EXPANSION OF PROMPT SEQUENCES in zshmisc(1).

    Shell Emulation

APPEND_CREATE <K> <S>
  This option only applies when NO_CLOBBER (-C) is in effect.

If this option is not set, the shell will report an error when a append redirection (>>) is used on a file that does not already exists (the traditional zsh behaviour of NO_CLOBBER). If the option is set, no error is reported (POSIX behaviour).

BASH_REMATCH
  When set, matches performed with the =~ operator will set the BASH_REMATCH array variable, instead of the default MATCH and match variables. The first element of the BASH_REMATCH array will contain the entire matched text and subsequent elements will contain extracted substrings. This option makes more sense when KSH_ARRAYS is also set, so that the entire matched portion is stored at index 0 and the first substring is at index 1. Without this option, the MATCH variable contains the entire matched text and the match array variable contains substrings.
BSD_ECHO <S>
  Make the echo builtin compatible with the BSD echo(1) command. This disables backslashed escape sequences in echo strings unless the -e option is specified.
CONTINUE_ON_ERROR
  If a fatal error is encountered (see the section ERRORS in zshmisc(1)), and the code is running in a script, the shell will resume execution at the next statement in the script at the top level, in other words outside all functions or shell constructs such as loops and conditions. This mimics the behaviour of interactive shells, where the shell returns to the line editor to read a new command; it was the normal behaviour in versions of zsh before 5.0.1.
CSH_JUNKIE_HISTORY <C>
  A history reference without an event specifier will always refer to the previous command. Without this option, such a history reference refers to the same event as the previous history reference on the current command line, defaulting to the previous command.
CSH_JUNKIE_LOOPS <C>
  Allow loop bodies to take the form ‘list; end’ instead of ‘do list; done’.
CSH_JUNKIE_QUOTES <C>
  Changes the rules for single- and double-quoted text to match that of csh. These require that embedded newlines be preceded by a backslash; unescaped newlines will cause an error message. In double-quoted strings, it is made impossible to escape ‘$’, ‘’ or ‘"’ (and ‘\’ itself no longer needs escaping). Command substitutions are only expanded once, and cannot be nested.
CSH_NULLCMD <C>
  Do not use the values of NULLCMD and READNULLCMD when running redirections with no command. This make such redirections fail (see the section ‘Redirection’).
KSH_ARRAYS <K> <S>
  Emulate ksh array handling as closely as possible. If this option is set, array elements are numbered from zero, an array parameter without subscript refers to the first element instead of the whole array, and braces are required to delimit a subscript (‘${path[2]}’ rather than just ‘$path[2]’).
KSH_AUTOLOAD <K> <S>
  Emulate ksh function autoloading. This means that when a function is autoloaded, the corresponding file is merely executed, and must define the function itself. (By default, the function is defined to the contents of the file. However, the most common ksh-style case - of the file containing only a simple definition of the function - is always handled in the ksh-compatible manner.)
KSH_OPTION_PRINT <K>
  Alters the way options settings are printed: instead of separate lists of set and unset options, all options are shown, marked ‘on’ if they are in the non-default state, ‘off’ otherwise.
KSH_TYPESET
  This option is now obsolete: a better appropximation to the behaviour of other shells is obtained with the reserved word interface to declare, export, float, integer, local, readonly and typeset. Note that the option is only applied when the reserved word interface is not in use.

Alters the way arguments to the typeset family of commands, including declare, export, float, integer, local and readonly, are processed. Without this option, zsh will perform normal word splitting after command and parameter expansion in arguments of an assignment; with it, word splitting does not take place in those cases.

KSH_ZERO_SUBSCRIPT
  Treat use of a subscript of value zero in array or string expressions as a reference to the first element, i.e. the element that usually has the subscript 1. Ignored if KSH_ARRAYS is also set.

If neither this option nor KSH_ARRAYS is set, accesses to an element of an array or string with subscript zero return an empty element or string, while attempts to set element zero of an array or string are treated as an error. However, attempts to set an otherwise valid subscript range that includes zero will succeed. For example, if KSH_ZERO_SUBSCRIPT is not set,

 
array[0]=(element)

is an error, while

 
array[0,1]=(element)

is not and will replace the first element of the array.

This option is for compatibility with older versions of the shell and is not recommended in new code.

POSIX_ALIASES <K> <S>
  When this option is set, reserved words are not candidates for alias expansion: it is still possible to declare any of them as an alias, but the alias will never be expanded. Reserved words are described in the section RESERVED WORDS in zshmisc(1).

Alias expansion takes place while text is being read; hence when this option is set it does not take effect until the end of any function or other piece of shell code parsed as one unit. Note this may cause differences from other shells even when the option is in effect. For example, when running a command with ‘zsh -c’, or even ‘zsh -o posixaliases -c’, the entire command argument is parsed as one unit, so aliases defined within the argument are not available even in later lines. If in doubt, avoid use of aliases in non-interactive code.

POSIX_ARGZERO
  This option may be used to temporarily disable FUNCTION_ARGZERO and thereby restore the value of $0 to the name used to invoke the shell (or as set by the -c command line option). For compatibility with previous versions of the shell, emulations use NO_FUNCTION_ARGZERO instead of POSIX_ARGZERO, which may result in unexpected scoping of $0 if the emulation mode is changed inside a function or script. To avoid this, explicitly enable POSIX_ARGZERO in the emulate command:

 
emulate sh -o POSIX_ARGZERO

Note that NO_POSIX_ARGZERO has no effect unless FUNCTION_ARGZERO was already enabled upon entry to the function or script.

POSIX_BUILTINS <K> <S>
  When this option is set the command builtin can be used to execute shell builtin commands. Parameter assignments specified before shell functions and special builtins are kept after the command completes unless the special builtin is prefixed with the command builtin. Special builtins are ., :, break, continue, declare, eval, exit, export, integer, local, readonly, return, set, shift, source, times, trap and unset.

In addition, various error conditions associated with the above builtins or exec cause a non-interactive shell to exit and an interactive shell to return to its top-level processing.

Furthermore, the getopts builtin behaves in a POSIX-compatible fashion in that the associated variable OPTIND is not made local to functions.

POSIX_IDENTIFIERS <K> <S>
  When this option is set, only the ASCII characters a to z, A to Z, 0 to 9 and _ may be used in identifiers (names of shell parameters and modules).

In addition, setting this option limits the effect of parameter substitution with no braces, so that the expression $# is treated as the parameter $# even if followed by a valid parameter name. When it is unset, zsh allows expressions of the form $#name to refer to the length of $name, even for special variables, for example in expressions such as $#- and $#*.

When the option is unset and multibyte character support is enabled (i.e. it is compiled in and the option MULTIBYTE is set), then additionally any alphanumeric characters in the local character set may be used in identifiers. Note that scripts and functions written with this feature are not portable, and also that both options must be set before the script or function is parsed; setting them during execution is not sufficient as the syntax variable=value has already been parsed as a command rather than an assignment.

If multibyte character support is not compiled into the shell this option is ignored; all octets with the top bit set may be used in identifiers. This is non-standard but is the traditional zsh behaviour.

POSIX_STRINGS <K> <S>
  This option affects processing of quoted strings. Currently it only affects the behaviour of null characters, i.e. character 0 in the portable character set corresponding to US ASCII.

When this option is not set, null characters embedded within strings of the form $’... are treated as ordinary characters. The entire string is maintained within the shell and output to files where necessary, although owing to restrictions of the library interface the string is truncated at the null character in file names, environment variables, or in arguments to external programs.

When this option is set, the $’... expression is truncated at the null character. Note that remaining parts of the same string beyond the termination of the quotes are not truncated.

For example, the command line argument a$’b\0c’d is treated with the option off as the characters a, b, null, c, d, and with the option on as the characters a, b, d.

POSIX_TRAPS <K> <S>
  When this option is set, the usual zsh behaviour of executing traps for EXIT on exit from shell functions is suppressed. In that case, manipulating EXIT traps always alters the global trap for exiting the shell; the LOCAL_TRAPS option is ignored for the EXIT trap. Furthermore, a return statement executed in a trap with no argument passes back from the function the value from the surrounding context, not from code executed within the trap.
SH_FILE_EXPANSION <K> <S>
  Perform filename expansion (e.g., ~ expansion) before parameter expansion, command substitution, arithmetic expansion and brace expansion. If this option is unset, it is performed after brace expansion, so things like ‘~$USERNAME’ and ‘~{pfalstad,rc}’ will work.
SH_NULLCMD <K> <S>
  Do not use the values of NULLCMD and READNULLCMD when doing redirections, use ‘:’ instead (see the section ‘Redirection’).
SH_OPTION_LETTERS <K> <S>
  If this option is set the shell tries to interpret single letter options (which are used with set and setopt) like ksh does. This also affects the value of the - special parameter.
SH_WORD_SPLIT (-y) <K> <S>
  Causes field splitting to be performed on unquoted parameter expansions. Note that this option has nothing to do with word splitting. (See the section ‘Parameter Expansion’.)
TRAPS_ASYNC
  While waiting for a program to exit, handle signals and run traps immediately. Otherwise the trap is run after a child process has exited. Note this does not affect the point at which traps are run for any case other than when the shell is waiting for a child process.

    Shell State

INTERACTIVE (-i, ksh: -i)
  This is an interactive shell. This option is set upon initialisation if the standard input is a tty and commands are being read from standard input. (See the discussion of SHIN_STDIN.) This heuristic may be overridden by specifying a state for this option on the command line. The value of this option can only be changed via flags supplied at invocation of the shell. It cannot be changed once zsh is running.
LOGIN (-l, ksh: -l)
  This is a login shell. If this option is not explicitly set, the shell becomes a login shell if the first character of the argv[0] passed to the shell is a ‘-’.
PRIVILEGED (-p, ksh: -p)
  Turn on privileged mode. Typically this is used when script is to be run with elevated privileges. This should be done as follows directly with the -p option to zsh so that it takes effect during startup.

 
#!/bin/zsh -p

The option is enabled automatically on startup if the effective user (group) ID is not equal to the real user (group) ID. In this case, turning the option off causes the effective user and group IDs to be set to the real user and group IDs. Be aware that if that fails the shell may be running with different IDs than was intended so a script should check for failure and act accordingly, for example:

 
unsetopt privileged || exit

The PRIVILEGED option disables sourcing user startup files. If zsh is invoked as ‘sh’ or ‘ksh’ with this option set, /etc/suid_profile is sourced (after /etc/profile on interactive shells). Sourcing ~/.profile is disabled and the contents of the ENV variable is ignored. This option cannot be changed using the -m option of setopt and unsetopt, and changing it inside a function always changes it globally regardless of the LOCAL_OPTIONS option.

RESTRICTED (-r)
  Enables restricted mode. This option cannot be changed using unsetopt, and setting it inside a function always changes it globally regardless of the LOCAL_OPTIONS option. See the section ‘Restricted Shell’.
SHIN_STDIN (-s, ksh: -s)
  Commands are being read from the standard input. Commands are read from standard input if no command is specified with -c and no file of commands is specified. If SHIN_STDIN is set explicitly on the command line, any argument that would otherwise have been taken as a file to run will instead be treated as a normal positional parameter. Note that setting or unsetting this option on the command line does not necessarily affect the state the option will have while the shell is running - that is purely an indicator of whether or not commands are actually being read from standard input. The value of this option can only be changed via flags supplied at invocation of the shell. It cannot be changed once zsh is running.
SINGLE_COMMAND (-t, ksh: -t)
  If the shell is reading from standard input, it exits after a single command has been executed. This also makes the shell non-interactive, unless the INTERACTIVE option is explicitly set on the command line. The value of this option can only be changed via flags supplied at invocation of the shell. It cannot be changed once zsh is running.

    Zle

BEEP (+B) <D>
  Beep on error in ZLE.
COMBINING_CHARS
  Assume that the terminal displays combining characters correctly. Specifically, if a base alphanumeric character is followed by one or more zero-width punctuation characters, assume that the zero-width characters will be displayed as modifications to the base character within the same width. Not all terminals handle this. If this option is not set, zero-width characters are displayed separately with special mark-up.

If this option is set, the pattern test [[:WORD:]] matches a zero-width punctuation character on the assumption that it will be used as part of a word in combination with a word character. Otherwise the base shell does not handle combining characters specially.

EMACS If ZLE is loaded, turning on this option has the equivalent effect of ‘bindkey -e’. In addition, the VI option is unset. Turning it off has no effect. The option setting is not guaranteed to reflect the current keymap. This option is provided for compatibility; bindkey is the recommended interface.
OVERSTRIKE
  Start up the line editor in overstrike mode.
SINGLE_LINE_ZLE (-M) <K>
  Use single-line command line editing instead of multi-line.

Note that although this is on by default in ksh emulation it only provides superficial compatibility with the ksh line editor and reduces the effectiveness of the zsh line editor. As it has no effect on shell syntax, many users may wish to disable this option when using ksh emulation interactively.

VI If ZLE is loaded, turning on this option has the equivalent effect of ‘bindkey -v’. In addition, the EMACS option is unset. Turning it off has no effect. The option setting is not guaranteed to reflect the current keymap. This option is provided for compatibility; bindkey is the recommended interface.
ZLE (-Z) Use the zsh line editor. Set by default in interactive shells connected to a terminal.

OPTION ALIASES

Some options have alternative names. These aliases are never used for output, but can be used just like normal option names when specifying options to the shell.

BRACE_EXPAND
  NO_IGNORE_BRACES (ksh and bash compatibility)
DOT_GLOB
  GLOB_DOTS (bash compatibility)
HASH_ALL
  HASH_CMDS (bash compatibility)
HIST_APPEND
  APPEND_HISTORY (bash compatibility)
HIST_EXPAND
  BANG_HIST (bash compatibility)
LOG NO_HIST_NO_FUNCTIONS (ksh compatibility)
MAIL_WARN
  MAIL_WARNING (bash compatibility)
ONE_CMD
  SINGLE_COMMAND (bash compatibility)
PHYSICAL
  CHASE_LINKS (ksh and bash compatibility)
PROMPT_VARS
  PROMPT_SUBST (bash compatibility)
STDIN SHIN_STDIN (ksh compatibility)
TRACK_ALL
  HASH_CMDS (ksh compatibility)

SINGLE LETTER OPTIONS

    Default set

-0 CORRECT
-1 PRINT_EXIT_VALUE
-2 NO_BAD_PATTERN
-3 NO_NOMATCH
-4 GLOB_DOTS
-5 NOTIFY
-6 BG_NICE
-7 IGNORE_EOF
-8 MARK_DIRS
-9 AUTO_LIST
-B NO_BEEP
-C NO_CLOBBER
-D PUSHD_TO_HOME
-E PUSHD_SILENT
-F NO_GLOB
-G NULL_GLOB
-H RM_STAR_SILENT
-I IGNORE_BRACES
-J AUTO_CD
-K NO_BANG_HIST
-L SUN_KEYBOARD_HACK
-M SINGLE_LINE_ZLE
-N AUTO_PUSHD
-O CORRECT_ALL
-P RC_EXPAND_PARAM
-Q PATH_DIRS
-R LONG_LIST_JOBS
-S REC_EXACT
-T CDABLE_VARS
-U MAIL_WARNING
-V NO_PROMPT_CR
-W AUTO_RESUME
-X LIST_TYPES
-Y MENU_COMPLETE
-Z ZLE
-a ALL_EXPORT
-e ERR_EXIT
-f NO_RCS
-g HIST_IGNORE_SPACE
-h HIST_IGNORE_DUPS
-i INTERACTIVE
-k INTERACTIVE_COMMENTS
-l LOGIN
-m MONITOR
-n NO_EXEC
-p PRIVILEGED
-r RESTRICTED
-s SHIN_STDIN
-t SINGLE_COMMAND
-u NO_UNSET
-v VERBOSE
-w CHASE_LINKS
-x XTRACE
-y SH_WORD_SPLIT

    sh/ksh emulation set

-C NO_CLOBBER
-T TRAPS_ASYNC
-X MARK_DIRS
-a ALL_EXPORT
-b NOTIFY
-e ERR_EXIT
-f NO_GLOB
-i INTERACTIVE
-l LOGIN
-m MONITOR
-n NO_EXEC
-p PRIVILEGED
-r RESTRICTED
-s SHIN_STDIN
-t SINGLE_COMMAND
-u NO_UNSET
-v VERBOSE
-x XTRACE

    Also note

-A Used by set for setting arrays
-b Used on the command line to specify end of option processing
-c Used on the command line to specify a single command
-m Used by setopt for pattern-matching option setting
-o Used in all places to allow use of long option names
-s Used by set to sort positional parameters

NAME

zshbuiltins - zsh built-in commands

SHELL BUILTIN COMMANDS

Some shell builtin commands take options as described in individual entries; these are often referred to in the list below as ‘flags’ to avoid confusion with shell options, which may also have an effect on the behaviour of builtin commands. In this introductory section, ‘option’ always has the meaning of an option to a command that should be familiar to most command line users.

Typically, options are single letters preceded by a hyphen (-). Options that take an argument accept it either immediately following the option letter or after white space, for example ‘print -C3 *’ or ‘print -C 3 *’ are equivalent. Arguments to options are not the same as arguments to the command; the documentation indicates which is which. Options that do not take an argument may be combined in a single word, for example ‘print -ca *’ and ‘print -c -a *’ are equivalent.

Some shell builtin commands also take options that begin with ‘+’ instead of ‘-’. The list below makes clear which commands these are.

Options (together with their individual arguments, if any) must appear in a group before any non-option arguments; once the first non-option argument has been found, option processing is terminated.

All builtin commands other than precommand modifiers, even those that have no options, can be given the argument ‘--’ to terminate option processing. This indicates that the following words are non-option arguments, but is otherwise ignored. This is useful in cases where arguments to the command may begin with ‘-’. For historical reasons, most builtin commands also recognize a single ‘-’ in a separate word for this purpose; note that this is less standard and use of ‘--’ is recommended.

- simple command
  See the section ‘Precommand Modifiers’ in zshmisc(1).
. file [ arg ... ]
  Read commands from file and execute them in the current shell environment.

If file does not contain a slash, or if PATH_DIRS is set, the shell looks in the components of $path to find the directory containing file. Files in the current directory are not read unless ‘.’ appears somewhere in $path. If a file named ‘file.zwc’ is found, is newer than file, and is the compiled form (created with the zcompile builtin) of file, then commands are read from that file instead of file.

If any arguments arg are given, they become the positional parameters; the old positional parameters are restored when the file is done executing. If file was not found the return status is 127; if file was found but contained a syntax error the return status is 126; else the return status is the exit status of the last command executed.

: [ arg ... ]
  This command does nothing, although normal argument expansions is performed which may have effects on shell parameters. A zero exit status is returned.
alias [ {+|-}gmrsL ] [ name[=value] ... ]
  For each name with a corresponding value, define an alias with that value. A trailing space in value causes the next word to be checked for alias expansion. If the -g flag is present, define a global alias; global aliases are expanded even if they do not occur in command position.

If the -s flag is present, define a suffix alias: if the command word on a command line is in the form ‘text.name’, where text is any non-empty string, it is replaced by the text ‘value text.name’. Note that name is treated as a literal string, not a pattern. A trailing space in value is not special in this case. For example,

 
alias -s ps=gv

will cause the command ‘*.ps’ to be expanded to ‘gv *.ps’. As alias expansion is carried out earlier than globbing, the ‘*.ps’ will then be expanded. Suffix aliases constitute a different name space from other aliases (so in the above example it is still possible to create an alias for the command ps) and the two sets are never listed together.

For each name with no value, print the value of name, if any. With no arguments, print all currently defined aliases other than suffix aliases. If the -m flag is given the arguments are taken as patterns (they should be quoted to preserve them from being interpreted as glob patterns), and the aliases matching these patterns are printed. When printing aliases and one of the -g, -r or -s flags is present, restrict the printing to global, regular or suffix aliases, respectively; a regular alias is one which is neither a global nor a suffix alias. Using ‘+’ instead of ‘-’, or ending the option list with a single ‘+’, prevents the values of the aliases from being printed.

If the -L flag is present, then print each alias in a manner suitable for putting in a startup script. The exit status is nonzero if a name (with no value) is given for which no alias has been defined.

For more on aliases, include common problems, see the section ALIASING in zshmisc(1).

autoload [ {+|-}TUXkmtz ] [ -w ] [ name ... ]
  Equivalent to functions -u, with the exception of -X/+X and -w. See the section ‘Autoloading Functions’ in zshmisc(1) for full details. The fpath parameter will be searched to find the function definition when the function is first referenced.

The flag -X may be used only inside a shell function, and may not be followed by a name. It causes the calling function to be marked for autoloading and then immediately loaded and executed, with the current array of positional parameters as arguments. This replaces the previous definition of the function. If no function definition is found, an error is printed and the function remains undefined and marked for autoloading.

The flag +X attempts to load each name as an autoloaded function, but does not execute it. The exit status is zero (success) if the function was not previously defined and a definition for it was found. This does not replace any existing definition of the function. The exit status is nonzero (failure) if the function was already defined or when no definition was found. In the latter case the function remains undefined and marked for autoloading. If ksh-style autoloading is enabled, the function created will contain the contents of the file plus a call to the function itself appended to it, thus giving normal ksh autoloading behaviour on the first call to the function. If the -m flag is also given each name is treated as a pattern and all functions already marked for autoload that match the pattern are loaded.

With the -w flag, the names are taken as names of files compiled with the zcompile builtin, and all functions defined in them are marked for autoloading.

The flags -z and -k mark the function to be autoloaded using the zsh or ksh style, as if the option KSH_AUTOLOAD were unset or were set, respectively. The flags override the setting of the option at the time the function is loaded.

Note that the autoload command makes no attempt to ensure the shell options set during the loading or execution of the file have any particular value. For this, the emulate command can be used:

 
emulate zsh -c ’autoload -Uz func

arranges that when func is loaded the shell is in native zsh emulation, and this emulation is also applied when func is run.

bg [ job ... ]
job ... &
  Put each specified job in the background, or the current job if none is specified.
bindkey
  See the section ‘Zle Builtins’ in zshzle(1).
break [ n ]
  Exit from an enclosing for, while, until, select or repeat loop. If an arithmetic expression n is specified, then break n levels instead of just one.
builtin name [ args ... ]
  Executes the builtin name, with the given args.
bye Same as exit.
cap See the section ‘The zsh/cap Module’ in zshmodules(1).
cd [ -qsLP ] [ arg ]
cd [ -qsLP ] old new
cd [ -qsLP ] {+|-}n
  Change the current directory. In the first form, change the current directory to arg, or to the value of $HOME if arg is not specified. If arg is ‘-’, change to the previous directory.

Otherwise, if arg begins with a slash, attempt to change to the directory given by arg.

If arg does not begin with a slash, the behaviour depends on whether the current directory ‘.’ occurs in the list of directories contained in the shell parameter cdpath. If it does not, first attempt to change to the directory arg under the current directory, and if that fails but cdpath is set and contains at least one element attempt to change to the directory arg under each component of cdpath in turn until successful. If ‘.’ occurs in cdpath, then cdpath is searched strictly in order so that ‘.’ is only tried at the appropriate point.

The order of testing cdpath is modified if the option POSIX_CD is set, as described in the documentation for the option.

If no directory is found, the option CDABLE_VARS is set, and a parameter named arg exists whose value begins with a slash, treat its value as the directory. In that case, the parameter is added to the named directory hash table.

The second form of cd substitutes the string new for the string old in the name of the current directory, and tries to change to this new directory.

The third form of cd extracts an entry from the directory stack, and changes to that directory. An argument of the form ‘+n’ identifies a stack entry by counting from the left of the list shown by the dirs command, starting with zero. An argument of the form ‘-n’ counts from the right. If the PUSHD_MINUS option is set, the meanings of ‘+’ and ‘-’ in this context are swapped.

If the -q (quiet) option is specified, the hook function chpwd and the functions in the array chpwd_functions are not called. This is useful for calls to cd that do not change the environment seen by an interactive user.

If the -s option is specified, cd refuses to change the current directory if the given pathname contains symlinks. If the -P option is given or the CHASE_LINKS option is set, symbolic links are resolved to their true values. If the -L option is given symbolic links are retained in the directory (and not resolved) regardless of the state of the CHASE_LINKS option.

chdir Same as cd.
clone See the section ‘The zsh/clone Module’ in zshmodules(1).
command [ -pvV ] simple command
  The simple command argument is taken as an external command instead of a function or builtin and is executed. If the POSIX_BUILTINS option is set, builtins will also be executed but certain special properties of them are suppressed. The -p flag causes a default path to be searched instead of that in $path. With the -v flag, command is similar to whence and with -V, it is equivalent to whence -v.

See also the section ‘Precommand Modifiers’ in zshmisc(1).

comparguments
  See the section ‘The zsh/computil Module’ in zshmodules(1).
compcall
  See the section ‘The zsh/compctl Module’ in zshmodules(1).
compctl
  See the section ‘The zsh/compctl Module’ in zshmodules(1).
compdescribe
  See the section ‘The zsh/computil Module’ in zshmodules(1).
compfiles
  See the section ‘The zsh/computil Module’ in zshmodules(1).
compgroups
  See the section ‘The zsh/computil Module’ in zshmodules(1).
compquote
  See the section ‘The zsh/computil Module’ in zshmodules(1).
comptags
  See the section ‘The zsh/computil Module’ in zshmodules(1).
comptry
  See the section ‘The zsh/computil Module’ in zshmodules(1).
compvalues
  See the section ‘The zsh/computil Module’ in zshmodules(1).
continue [ n ]
  Resume the next iteration of the enclosing for, while, until, select or repeat loop. If an arithmetic expression n is specified, break out of n-1 loops and resume at the nth enclosing loop.
declare
  Same as typeset.
dirs [ -c ] [ arg ... ]
dirs [ -lpv ]
  With no arguments, print the contents of the directory stack. Directories are added to this stack with the pushd command, and removed with the cd or popd commands. If arguments are specified, load them onto the directory stack, replacing anything that was there, and push the current directory onto the stack.

-c clear the directory stack.
-l print directory names in full instead of using of using ~ expressions (see Dynamic and Static named directories in zshexpn(1)).
-p print directory entries one per line.
-v number the directories in the stack when printing.

disable [ -afmprs ] name ...
  Temporarily disable the named hash table elements or patterns. The default is to disable builtin commands. This allows you to use an external command with the same name as a builtin command. The -a option causes disable to act on regular or global aliases. The -s option causes disable to act on suffix aliases. The -f option causes disable to act on shell functions. The -r options causes disable to act on reserved words. Without arguments all disabled hash table elements from the corresponding hash table are printed. With the -m flag the arguments are taken as patterns (which should be quoted to prevent them from undergoing filename expansion), and all hash table elements from the corresponding hash table matching these patterns are disabled. Disabled objects can be enabled with the enable command.

With the option -p, name ... refer to elements of the shell’s pattern syntax as described in the section ‘Filename Generation’. Certain elements can be disabled separately, as given below.

Note that patterns not allowed by the current settings for the options EXTENDED_GLOB, KSH_GLOB and SH_GLOB are never enabled, regardless of the setting here. For example, if EXTENDED_GLOB is not active, the pattern ^ is ineffective even if ‘disable -p "^"’ has not been issued. The list below indicates any option settings that restrict the use of the pattern. It should be noted that setting SH_GLOB has a wider effect than merely disabling patterns as certain expressions, in particular those involving parentheses, are parsed differently.

The following patterns may be disabled; all the strings need quoting on the command line to prevent them from being interpreted immediately as patterns and the patterns are shown below in single quotes as a reminder.

’?’ The pattern character ? wherever it occurs, including when preceding a parenthesis with KSH_GLOB.
’*’ The pattern character * wherever it occurs, including recursive globbing and when preceding a parenthesis with KSH_GLOB.
’[’ Character classes.
’<’ (NO_SH_GLOB)
  Numeric ranges.
’|’ (NO_SH_GLOB)
  Alternation in grouped patterns, case statements, or KSH_GLOB parenthesised expressions.
’(’ (NO_SH_GLOB)
  Grouping using single parentheses. Disabling this does not disable the use of parentheses for KSH_GLOB where they are introduced by a special character, nor for glob qualifiers (use ‘setopt NO_BARE_GLOB_QUAL’ to disable glob qualifiers that use parentheses only).
’~’ (EXTENDED_GLOB)
  Exclusion in the form A~B.
’^’ (EXTENDED_GLOB)
  Exclusion in the form A^B.
’#’ (EXTENDED_GLOB)
  The pattern character # wherever it occurs, both for repetition of a previous pattern and for indicating globbing flags.
’?(’ (KSH_GLOB)
  The grouping form ?(...). Note this is also disabled if ’?’ is disabled.
’*(’ (KSH_GLOB)
  The grouping form *(...). Note this is also disabled if ’*’ is disabled.
’+(’ (KSH_GLOB)
  The grouping form +(...).
’!(’ (KSH_GLOB)
  The grouping form !(...).
’@(’ (KSH_GLOB)
  The grouping form @(...).

disown [ job ... ]
job ... &|
job ... &!
  Remove the specified jobs from the job table; the shell will no longer report their status, and will not complain if you try to exit an interactive shell with them running or stopped. If no job is specified, disown the current job.

If the jobs are currently stopped and the AUTO_CONTINUE option is not set, a warning is printed containing information about how to make them running after they have been disowned. If one of the latter two forms is used, the jobs will automatically be made running, independent of the setting of the AUTO_CONTINUE option.

echo [ -neE ] [ arg ... ]
  Write each arg on the standard output, with a space separating each one. If the -n flag is not present, print a newline at the end. echo recognizes the following escape sequences:

\a bell character
\b backspace
\c suppress final newline
\e escape
\f form feed
\n linefeed (newline)
\r carriage return
\t horizontal tab
\v vertical tab
\\ backslash
\0NNN character code in octal
\xNN character code in hexadecimal
\uNNNN unicode character code in hexadecimal
\UNNNNNNNN
  unicode character code in hexadecimal
The -E flag, or the BSD_ECHO option, can be used to disable these escape sequences. In the latter case, -e flag can be used to enable them.

echotc See the section ‘The zsh/termcap Module’ in zshmodules(1).
echoti See the section ‘The zsh/terminfo Module’ in zshmodules(1).
emulate [ -lLR ] [ {zsh|sh|ksh|csh} [ flags ... ] ]
  Without any argument print current emulation mode.

With single argument set up zsh options to emulate the specified shell as much as possible. csh will never be fully emulated. If the argument is not one of the shells listed above, zsh will be used as a default; more precisely, the tests performed on the argument are the same as those used to determine the emulation at startup based on the shell name, see the section COMPATIBILITY in zsh(1) . In addition to setting shell options, the command also restores the pristine state of pattern enables, as if all patterns had been enabled using enable -p.

If the emulate command occurs inside a function that has been marked for execution tracing with functions -t then the xtrace option will be turned on regardless of emulation mode or other options. Note that code executed inside the function by the ., source, or eval commands is not considered to be running directly from the function, hence does not provoke this behaviour.

If the -R switch is given, all settable options are reset to their default value corresponding to the specified emulation mode, except for certain options describing the interactive environment; otherwise, only those options likely to cause portability problems in scripts and functions are altered. If the -L switch is given, the options LOCAL_OPTIONS, LOCAL_PATTERNS and LOCAL_TRAPS will be set as well, causing the effects of the emulate command and any setopt, disable -p or enable -p, and trap commands to be local to the immediately surrounding shell function, if any; normally these options are turned off in all emulation modes except ksh. The -L switch is mutually exclusive with the use of -c in flags.

If there is a single argument and the -l switch is given, the options that would be set or unset (the latter indicated with the prefix ‘no’) are listed. -l can be combined with -L or -R and the list will be modified in the appropriate way. Note the list does not depend on the current setting of options, i.e. it includes all options that may in principle change, not just those that would actually change.

The flags may be any of the invocation-time flags described in the section INVOCATION in zsh(1), except that ‘-o EMACS’ and ‘-o VI’ may not be used. Flags such as ‘+r’/‘+o RESTRICTED’ may be prohibited in some circumstances.

If -c arg appears in flags, arg is evaluated while the requested emulation is temporarily in effect. In this case the emulation mode and all options are restored to their previous values before emulate returns. The -R switch may precede the name of the shell to emulate; note this has a meaning distinct from including -R in flags.

Use of -c enables ‘sticky’ emulation mode for functions defined within the evaluated expression: the emulation mode is associated thereafter with the function so that whenever the function is executed the emulation (respecting the -R switch, if present) and all options are set (and pattern disables cleared) before entry to the function, and the state is restored after exit. If the function is called when the sticky emulation is already in effect, either within an ‘emulate shell -c’ expression or within another function with the same sticky emulation, entry and exit from the function do not cause options to be altered (except due to standard processing such as the LOCAL_OPTIONS option). This also applies to functions marked for autoload within the sticky emulation; the appropriate set of options will be applied at the point the function is loaded as well as when it is run.

For example:

 
emulate sh -c ’fni() { setopt cshnullglob; }
fno() { fni; }’
fno

The two functions fni and fno are defined with sticky sh emulation. fno is then executed, causing options associated with emulations to be set to their values in sh. fno then calls fni; because fni is also marked for sticky sh emulation, no option changes take place on entry to or exit from it. Hence the option cshnullglob, turned off by sh emulation, will be turned on within fni and remain on on return to fno. On exit from fno, the emulation mode and all options will be restored to the state they were in before entry to the temporary emulation.

The documentation above is typically sufficient for the intended purpose of executing code designed for other shells in a suitable environment. More detailed rules follow.
1. The sticky emulation environment provided by ‘emulate shell -c’ is identical to that provided by entry to a function marked for sticky emulation as a consequence of being defined in such an environment. Hence, for example, the sticky emulation is inherited by subfunctions defined within functions with sticky emulation.
2. No change of options takes place on entry to or exit from functions that are not marked for sticky emulation, other than those that would normally take place, even if those functions are called within sticky emulation.
3. No special handling is provided for functions marked for autoload nor for functions present in wordcode created by the zcompile command.
4. The presence or absence of the -R switch to emulate corresponds to different sticky emulation modes, so for example ‘emulate sh -c’, ‘emulate -R sh -c’ and ‘emulate csh -c’ are treated as three distinct sticky emulations.
5. Difference in shell options supplied in addition to the basic emulation also mean the sticky emulations are different, so for example ‘emulate zsh -c’ and ‘emulate zsh -o cbases -c’ are treated as distinct sticky emulations.

enable [ -afmprs ] name ...
  Enable the named hash table elements, presumably disabled earlier with disable. The default is to enable builtin commands. The -a option causes enable to act on regular or global aliases. The -s option causes enable to act on suffix aliases. The -f option causes enable to act on shell functions. The -r option causes enable to act on reserved words. Without arguments all enabled hash table elements from the corresponding hash table are printed. With the -m flag the arguments are taken as patterns (should be quoted) and all hash table elements from the corresponding hash table matching these patterns are enabled. Enabled objects can be disabled with the disable builtin command.

enable -p reenables patterns disabled with disable -p. Note that it does not override globbing options; for example, ‘enable -p "~"’ does not cause the pattern character ~ to be active unless the EXTENDED_GLOB option is also set. To enable all possible patterns (so that they may be individually disabled with disable -p), use ‘setopt EXTENDED_GLOB KSH_GLOB NO_SH_GLOB’.

eval [ arg ... ]
  Read the arguments as input to the shell and execute the resulting command(s) in the current shell process. The return status is the same as if the commands had been executed directly by the shell; if there are no args or they contain no commands (i.e. are an empty string or whitespace) the return status is zero.
exec [ -cl ] [ -a argv0 ] [ command [ arg ... ] ]
  Replace the current shell with an external command rather than forking. With -c clear the environment; with -l prepend - to the argv[0] string of the command executed (to simulate a login shell); with -a argv0 set the argv[0] string of the command executed. See the section ‘Precommand Modifiers’ in zshmisc(1).

If command is omitted but any redirections are specified, then the redirections will take effect in the current shell.

exit [ n ]
  Exit the shell with the exit status specified by an arithmetic expression n; if none is specified, use the exit status from the last command executed. An EOF condition will also cause the shell to exit, unless the IGNORE_EOF option is set.

See notes at the end of the section JOBS in in zshmisc(1) for some possibly unexpected interactions of the exit command with jobs.

export [ name[=value] ... ]
  The specified names are marked for automatic export to the environment of subsequently executed commands. Equivalent to typeset -gx. If a parameter specified does not already exist, it is created in the global scope.
false [ arg ... ]
  Do nothing and return an exit status of 1.

fc [ -e ename ] [ -LI ] [ -m match ] [ old=new ... ] [ first [ last ] ]
fc -l [ -LI ] [ -nrdfEiD ] [ -t timefmt ] [ -m match ]
[ old=new ... ] [ first [ last ] ]
fc -p [ -a ] [ filename [ histsize [ savehistsize ] ] ]
fc -P
fc -ARWI [ filename ]
  The fc command controls the interactive history mechanism. Note that reading and writing of history options is only performed if the shell is interactive. Usually this is detected automatically, but it can be forced by setting the interactive option when starting the shell.

The first two forms of this command select a range of events from first to last from the history list. The arguments first and last may be specified as a number or as a string. A negative number is used as an offset to the current history event number. A string specifies the most recent event beginning with the given string. All substitutions old=new, if any, are then performed on the text of the events.

In addition to the the number range,
-I restricts to only internal events (not from $HISTFILE)
-L restricts to only local events (not from other shells, see SHARE_HISTORY in zshoptions(1) -- note that $HISTFILE is considered local when read at startup)
-m takes the first argument as a pattern (should be quoted) and only the history events matching this pattern are considered
If first is not specified, it will be set to -1 (the most recent event), or to -16 if the -l flag is given. If last is not specified, it will be set to first, or to -1 if the -l flag is given. However, if the current event has added entries to the history with ‘print -s’ or ‘fc -R’, then the default last for -l includes all new history entries since the current event began.
When the -l flag is given, the resulting events are listed on standard output. Otherwise the editor program ename is invoked on a file containing these history events. If ename is not given, the value of the parameter FCEDIT is used; if that is not set the value of the parameter EDITOR is used; if that is not set a builtin default, usually ‘vi’ is used. If ename is ‘-’, no editor is invoked. When editing is complete, the edited command is executed.
The flag -r reverses the order of the events and the flag -n suppresses event numbers when listing.
Also when listing,
-d prints timestamps for each event
-f prints full time-date stamps in the US ‘MM/DD/YY hh:mm’ format
-E prints full time-date stamps in the European ‘dd.mm.yyyy hh:mm’ format
-i prints full time-date stamps in ISO8601 ‘yyyy-mm-dd hh:mm’ format
-t fmt prints time and date stamps in the given format; fmt is formatted with the strftime function with the zsh extensions described for the %D{string} prompt format in the section EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The resulting formatted string must be no more than 256 characters or will not be printed
-D prints elapsed times; may be combined with one of the options above
fc -p’ pushes the current history list onto a stack and switches to a new history list. If the -a option is also specified, this history list will be automatically popped when the current function scope is exited, which is a much better solution than creating a trap function to call ‘fc -P’ manually. If no arguments are specified, the history list is left empty, $HISTFILE is unset, and $HISTSIZE & $SAVEHIST are set to their default values. If one argument is given, $HISTFILE is set to that filename, $HISTSIZE & $SAVEHIST are left unchanged, and the history file is read in (if it exists) to initialize the new list. If a second argument is specified, $HISTSIZE & $SAVEHIST are instead set to the single specified numeric value. Finally, if a third argument is specified, $SAVEHIST is set to a separate value from $HISTSIZE. You are free to change these environment values for the new history list however you desire in order to manipulate the new history list.

fc -P’ pops the history list back to an older list saved by ‘fc -p’. The current list is saved to its $HISTFILE before it is destroyed (assuming that $HISTFILE and $SAVEHIST are set appropriately, of course). The values of $HISTFILE, $HISTSIZE, and $SAVEHIST are restored to the values they had when ‘fc -p’ was called. Note that this restoration can conflict with making these variables "local", so your best bet is to avoid local declarations for these variables in functions that use ‘fc -p’. The one other guaranteed-safe combination is declaring these variables to be local at the top of your function and using the automatic option (-a) with ‘fc -p’. Finally, note that it is legal to manually pop a push marked for automatic popping if you need to do so before the function exits.

fc -R’ reads the history from the given file, ‘fc -W’ writes the history out to the given file, and ‘fc -A’ appends the history out to the given file. If no filename is specified, the $HISTFILE is assumed. If the -I option is added to -R, only those events that are not already contained within the internal history list are added. If the -I option is added to -A or -W, only those events that are new since last incremental append/write to the history file are appended/written. In any case, the created file will have no more than $SAVEHIST entries.

fg [ job ... ]
job ...
  Bring each specified job in turn to the foreground. If no job is specified, resume the current job.
float [ {+|-}Hghlprtux ] [ {+|-}EFLRZ [ n ] ] [ name[=value] ... ]
  Equivalent to typeset -E, except that options irrelevant to floating point numbers are not permitted.
functions [ {+|-}UkmtTuz ] [ -x num ] [ name ... ]
functions -M mathfn [ min [ max [ shellfn ] ] ]
functions -M [ -m pattern ... ]
functions +M [ -m ] mathfn ...
  Equivalent to typeset -f, with the exception of the -x and -M options.

The -x option indicates that any functions output will have each leading tab for indentation, added by the shell to show syntactic structure, expanded to the given number num of spaces. num can also be 0 to suppress all indentation.

Use of the -M option may not be combined with any of the options handled by typeset -f.

functions -M mathfn defines mathfn as the name of a mathematical function recognised in all forms of arithmetical expressions; see the section ‘Arithmetic Evaluation’ in zshmisc(1). By default mathfn may take any number of comma-separated arguments. If min is given, it must have exactly min args; if min and max are both given, it must have at least min and at most max args. max may be -1 to indicate that there is no upper limit.

By default the function is implemented by a shell function of the same name; if shellfn is specified it gives the name of the corresponding shell function while mathfn remains the name used in arithmetical expressions. The name of the function in $0 is mathfn (not shellfn as would usually be the case), provided the option FUNCTION_ARGZERO is in effect. The positional parameters in the shell function correspond to the arguments of the mathematical function call. The result of the last arithmetical expression evaluated inside the shell function (even if it is a form that normally only returns a status) gives the result of the mathematical function.

functions -M with no arguments lists all such user-defined functions in the same form as a definition. With the additional option -m and a list of arguments, all functions whose mathfn matches one of the pattern arguments are listed.

function +M removes the list of mathematical functions; with the additional option -m the arguments are treated as patterns and all functions whose mathfn matches the pattern are removed. Note that the shell function implementing the behaviour is not removed (regardless of whether its name coincides with mathfn).

For example, the following prints the cube of 3:

 
zmath_cube() { (( $1 * $1 * $1 )) }
functions -M cube 1 1 zmath_cube
print $(( cube(3) ))

getcap See the section ‘The zsh/cap Module’ in zshmodules(1).
getln [ -AclneE ] name ...
  Read the top value from the buffer stack and put it in the shell parameter name. Equivalent to read -zr.
getopts optstring name [ arg ... ]
  Checks the args for legal options. If the args are omitted, use the positional parameters. A valid option argument begins with a ‘+’ or a ‘-’. An argument not beginning with a ‘+’ or a ‘-’, or the argument ‘--’, ends the options. Note that a single ‘-’ is not considered a valid option argument. optstring contains the letters that getopts recognizes. If a letter is followed by a ‘:’, that option requires an argument. The options can be separated from the argument by blanks.

Each time it is invoked, getopts places the option letter it finds in the shell parameter name, prepended with a ‘+’ when arg begins with a ‘+’. The index of the next arg is stored in OPTIND. The option argument, if any, is stored in OPTARG.

The first option to be examined may be changed by explicitly assigning to OPTIND. OPTIND has an initial value of 1, and is normally set to 1 upon entry to a shell function and restored upon exit (this is disabled by the POSIX_BUILTINS option). OPTARG is not reset and retains its value from the most recent call to getopts. If either of OPTIND or OPTARG is explicitly unset, it remains unset, and the index or option argument is not stored. The option itself is still stored in name in this case.

A leading ‘:’ in optstring causes getopts to store the letter of any invalid option in OPTARG, and to set name to ‘?’ for an unknown option and to ‘:’ when a required argument is missing. Otherwise, getopts sets name to ‘?’ and prints an error message when an option is invalid. The exit status is nonzero when there are no more options.

hash [ -Ldfmrv ] [ name[=value] ] ...
  hash can be used to directly modify the contents of the command hash table, and the named directory hash table. Normally one would modify these tables by modifying one’s PATH (for the command hash table) or by creating appropriate shell parameters (for the named directory hash table). The choice of hash table to work on is determined by the -d option; without the option the command hash table is used, and with the option the named directory hash table is used.

Given no arguments, and neither the -r or -f options, the selected hash table will be listed in full.

The -r option causes the selected hash table to be emptied. It will be subsequently rebuilt in the normal fashion. The -f option causes the selected hash table to be fully rebuilt immediately. For the command hash table this hashes all the absolute directories in the PATH, and for the named directory hash table this adds all users’ home directories. These two options cannot be used with any arguments.

The -m option causes the arguments to be taken as patterns (which should be quoted) and the elements of the hash table matching those patterns are printed. This is the only way to display a limited selection of hash table elements.

For each name with a corresponding value, put ‘name’ in the selected hash table, associating it with the pathname ‘value’. In the command hash table, this means that whenever ‘name’ is used as a command argument, the shell will try to execute the file given by ‘value’. In the named directory hash table, this means that ‘value’ may be referred to as ‘~name’.

For each name with no corresponding value, attempt to add name to the hash table, checking what the appropriate value is in the normal manner for that hash table. If an appropriate value can’t be found, then the hash table will be unchanged.

The -v option causes hash table entries to be listed as they are added by explicit specification. If has no effect if used with -f.

If the -L flag is present, then each hash table entry is printed in the form of a call to hash.

history
  Same as fc -l.
integer [ {+|-}Hghlprtux ] [ {+|-}LRZi [ n ] ] [ name[=value] ... ]
  Equivalent to typeset -i, except that options irrelevant to integers are not permitted.
jobs [ -dlprs ] [ job ... ]
jobs -Z string
  Lists information about each given job, or all jobs if job is omitted. The -l flag lists process IDs, and the -p flag lists process groups. If the -r flag is specified only running jobs will be listed and if the -s flag is given only stopped jobs are shown. If the -d flag is given, the directory from which the job was started (which may not be the current directory of the job) will also be shown.

The -Z option replaces the shell’s argument and environment space with the given string, truncated if necessary to fit. This will normally be visible in ps (ps(1)) listings. This feature is typically used by daemons, to indicate their state.

kill [ -s signal_name | -n signal_number | -sig ] job ...
kill -l [ sig ... ]
  Sends either SIGTERM or the specified signal to the given jobs or processes. Signals are given by number or by names, with or without the ‘SIG’ prefix. If the signal being sent is not ‘KILL’ or ‘CONT’, then the job will be sent a ‘CONT’ signal if it is stopped. The argument job can be the process ID of a job not in the job list. In the second form, kill -l, if sig is not specified the signal names are listed. Otherwise, for each sig that is a name, the corresponding signal number is listed. For each sig that is a signal number or a number representing the exit status of a process which was terminated or stopped by a signal the name of the signal is printed.

On some systems, alternative signal names are allowed for a few signals. Typical examples are SIGCHLD and SIGCLD or SIGPOLL and SIGIO, assuming they correspond to the same signal number. kill -l will only list the preferred form, however kill -l alt will show if the alternative form corresponds to a signal number. For example, under Linux kill -l IO and kill -l POLL both output 29, hence kill -IO and kill -POLL have the same effect.

Many systems will allow process IDs to be negative to kill a process group or zero to kill the current process group.

let arg ...
  Evaluate each arg as an arithmetic expression. See the section ‘Arithmetic Evaluation’ in zshmisc(1) for a description of arithmetic expressions. The exit status is 0 if the value of the last expression is nonzero, 1 if it is zero, and 2 if an error occurred.
limit [ -hs ] [ resource [ limit ] ] ...
  Set or display resource limits. Unless the -s flag is given, the limit applies only the children of the shell. If -s is given without other arguments, the resource limits of the current shell is set to the previously set resource limits of the children.

If limit is not specified, print the current limit placed on resource, otherwise set the limit to the specified value. If the -h flag is given, use hard limits instead of soft limits. If no resource is given, print all limits.

When looping over multiple resources, the shell will abort immediately if it detects a badly formed argument. However, if it fails to set a limit for some other reason it will continue trying to set the remaining limits.

resource can be one of:

addressspace
  Maximum amount of address space used.
aiomemorylocked
  Maximum amount of memory locked in RAM for AIO operations.
aiooperations
  Maximum number of AIO operations.
cachedthreads
  Maximum number of cached threads.
coredumpsize
  Maximum size of a core dump.
cputime
  Maximum CPU seconds per process.
datasize
  Maximum data size (including stack) for each process.
descriptors
  Maximum value for a file descriptor.
filesize
  Largest single file allowed.
kqueues
  Maximum number of kqueues allocated.
maxproc
  Maximum number of processes.
maxpthreads
  Maximum number of threads per process.
memorylocked
  Maximum amount of memory locked in RAM.
memoryuse
  Maximum resident set size.
msgqueue
  Maximum number of bytes in POSIX message queues.
posixlocks
  Maximum number of POSIX locks per user.
pseudoterminals
  Maximum number of pseudo-terminals.
resident
  Maximum resident set size.
sigpending
  Maximum number of pending signals.
sockbufsize
  Maximum size of all socket buffers.
stacksize
  Maximum stack size for each process.
swapsize
  Maximum amount of swap used.
vmemorysize
  Maximum amount of virtual memory.
Which of these resource limits are available depends on the system. resource can be abbreviated to any unambiguous prefix. It can also be an integer, which corresponds to the integer defined for the resource by the operating system.
If argument corresponds to a number which is out of the range of the resources configured into the shell, the shell will try to read or write the limit anyway, and will report an error if this fails. As the shell does not store such resources internally, an attempt to set the limit will fail unless the -s option is present.
limit is a number, with an optional scaling factor, as follows:
nh hours
nk kilobytes (default)
nm megabytes or minutes
[mm:]ss
  minutes and seconds
The limit command is not made available by default when the shell starts in a mode emulating another shell. It can be made available with the command ‘zmodload -F zsh/rlimits b:limit’.

local [ {+|-}AHUahlprtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] ... ]
  Same as typeset, except that the options -g, and -f are not permitted. In this case the -x option does not force the use of -g, i.e. exported variables will be local to functions.
log List all users currently logged in who are affected by the current setting of the watch parameter.
logout [ n ]
  Same as exit, except that it only works in a login shell.
noglob simple command
  See the section ‘Precommand Modifiers’ in zshmisc(1).
popd [ -q ] [ {+|-}n ]
  Remove an entry from the directory stack, and perform a cd to the new top directory. With no argument, the current top entry is removed. An argument of the form ‘+n’ identifies a stack entry by counting from the left of the list shown by the dirs command, starting with zero. An argument of the form -n counts from the right. If the PUSHD_MINUS option is set, the meanings of ‘+’ and ‘-’ in this context are swapped.

If the -q (quiet) option is specified, the hook function chpwd and the functions in the array $chpwd_functions are not called, and the new directory stack is not printed. This is useful for calls to popd that do not change the environment seen by an interactive user.

print [ -abcDilmnNoOpPrsSz ] [ -u n ] [ -f format ] [ -C cols ]
[ -xX tab-stop ] [ -R [ -en ]] [ arg ... ]
  With the ‘-f’ option the arguments are printed as described by printf. With no flags or with the flag ‘-’, the arguments are printed on the standard output as described by echo, with the following differences: the escape sequence ‘\M-x’ (or ‘\Mx’) metafies the character x (sets the highest bit), ‘\C-x’ (or ‘\Cx’) produces a control character (‘\C-@’ and ‘\C-?’ give the characters NULL and delete), a character code in octal is represented by ‘\NNN’ (instead of ‘\0NNN’), and ‘\E’ is a synonym for ‘\e’. Finally, if not in an escape sequence, ‘\’ escapes the following character and is not printed.

-a Print arguments with the column incrementing first. Only useful with the -c and -C options.
-b Recognize all the escape sequences defined for the bindkey command, see the section ‘Zle Builtins’ in zshzle(1).
-c Print the arguments in columns. Unless -a is also given, arguments are printed with the row incrementing first.
-C cols Print the arguments in cols columns. Unless -a is also given, arguments are printed with the row incrementing first.
-D Treat the arguments as paths, replacing directory prefixes with ~ expressions corresponding to directory names, as appropriate.
-i If given together with -o or -O, sorting is performed case-independently.
-l Print the arguments separated by newlines instead of spaces.
-m Take the first argument as a pattern (should be quoted), and remove it from the argument list together with subsequent arguments that do not match this pattern.
-n Do not add a newline to the output.
-N Print the arguments separated and terminated by nulls.
-o Print the arguments sorted in ascending order.
-O Print the arguments sorted in descending order.
-p Print the arguments to the input of the coprocess.
-P Perform prompt expansion (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)).
-r Ignore the escape conventions of echo.
-R Emulate the BSD echo command, which does not process escape sequences unless the -e flag is given. The -n flag suppresses the trailing newline. Only the -e and -n flags are recognized after -R; all other arguments and options are printed.
-s Place the results in the history list instead of on the standard output. Each argument to the print command is treated as a single word in the history, regardless of its content.
-S Place the results in the history list instead of on the standard output. In this case only a single argument is allowed; it will be split into words as if it were a full shell command line. The effect is similar to reading the line from a history file with the HIST_LEX_WORDS option active.
-u n Print the arguments to file descriptor n.
-x tab-stop
  Expand leading tabs on each line of output in the printed string assuming a tab stop every tab-stop characters. This is appropriate for formatting code that may be indented with tabs. Note that leading tabs of any argument to print, not just the first, are expanded, even if print is using spaces to separate arguments (the column count is maintained across arguments but may be incorrect on output owing to previous unexpanded tabs).

The start of the output of each print command is assumed to be aligned with a tab stop. Widths of multibyte characters are handled if the option MULTIBYTE is in effect. This option is ignored if other formatting options are in effect, namely column alignment or printf style, or if output is to a special location such as shell history or the command line editor.

-X tab-stop
  This is similar to -x, except that all tabs in the printed string are expanded. This is appropriate if tabs in the arguments are being used to produce a table format.
-z Push the arguments onto the editing buffer stack, separated by spaces.
If any of ‘-m’, ‘-o’ or ‘-O’ are used in combination with ‘-f’ and there are no arguments (after the removal process in the case of ‘-m’) then nothing is printed.

printf format [ arg ... ]
  Print the arguments according to the format specification. Formatting rules are the same as used in C. The same escape sequences as for echo are recognised in the format. All C conversion specifications ending in one of csdiouxXeEfgGn are handled. In addition to this, ‘%b’ can be used instead of ‘%s’ to cause escape sequences in the argument to be recognised and ‘%q’ can be used to quote the argument in such a way that allows it to be reused as shell input. With the numeric format specifiers, if the corresponding argument starts with a quote character, the numeric value of the following character is used as the number to print; otherwise the argument is evaluated as an arithmetic expression. See the section ‘Arithmetic Evaluation’ in zshmisc(1) for a description of arithmetic expressions. With ‘%n’, the corresponding argument is taken as an identifier which is created as an integer parameter.

Normally, conversion specifications are applied to each argument in order but they can explicitly specify the nth argument is to be used by replacing ‘%’ by ‘%n$’ and ‘*’ by ‘*n$’. It is recommended that you do not mix references of this explicit style with the normal style and the handling of such mixed styles may be subject to future change.

If arguments remain unused after formatting, the format string is reused until all arguments have been consumed. With the print builtin, this can be suppressed by using the -r option. If more arguments are required by the format than have been specified, the behaviour is as if zero or an empty string had been specified as the argument.

pushd [ -qsLP ] [ arg ]
pushd [ -qsLP ] old new
pushd [ -qsLP ] {+|-}n
  Change the current directory, and push the old current directory onto the directory stack. In the first form, change the current directory to arg. If arg is not specified, change to the second directory on the stack (that is, exchange the top two entries), or change to $HOME if the PUSHD_TO_HOME option is set or if there is only one entry on the stack. Otherwise, arg is interpreted as it would be by cd. The meaning of old and new in the second form is also the same as for cd.

The third form of pushd changes directory by rotating the directory list. An argument of the form ‘+n’ identifies a stack entry by counting from the left of the list shown by the dirs command, starting with zero. An argument of the form ‘-n’ counts from the right. If the PUSHD_MINUS option is set, the meanings of ‘+’ and ‘-’ in this context are swapped.

If the -q (quiet) option is specified, the hook function chpwd and the functions in the array $chpwd_functions are not called, and the new directory stack is not printed. This is useful for calls to pushd that do not change the environment seen by an interactive user.

If the option -q is not specified and the shell option PUSHD_SILENT is not set, the directory stack will be printed after a pushd is performed.

The options -s, -L and -P have the same meanings as for the cd builtin.

pushln [ arg ... ]
  Equivalent to print -nz.
pwd [ -rLP ]
  Print the absolute pathname of the current working directory. If the -r or the -P flag is specified, or the CHASE_LINKS option is set and the -L flag is not given, the printed path will not contain symbolic links.
r Same as fc -e -.

read [ -rszpqAclneE ] [ -t [ num ] ] [ -k [ num ] ] [ -d delim ]
[ -u n ] [ name[?prompt] ] [ name ... ]
  Read one line and break it into fields using the characters in $IFS as separators, except as noted below. The first field is assigned to the first name, the second field to the second name, etc., with leftover fields assigned to the last name. If name is omitted then REPLY is used for scalars and reply for arrays.

-r Raw mode: a ‘\’ at the end of a line does not signify line continuation and backslashes in the line don’t quote the following character and are not removed.
-s Don’t echo back characters if reading from the terminal.
-q Read only one character from the terminal and set name to ‘y’ if this character was ‘y’ or ‘Y’ and to ‘n’ otherwise. With this flag set the return status is zero only if the character was ‘y’ or ‘Y’. This option may be used with a timeout (see -t); if the read times out, or encounters end of file, status 2 is returned. Input is read from the terminal unless one of -u or -p is present. This option may also be used within zle widgets.
-k [ num ]
  Read only one (or num) characters. All are assigned to the first name, without word splitting. This flag is ignored when -q is present. Input is read from the terminal unless one of -u or -p is present. This option may also be used within zle widgets.

Note that despite the mnemonic ‘key’ this option does read full characters, which may consist of multiple bytes if the option MULTIBYTE is set.

-z Read one entry from the editor buffer stack and assign it to the first name, without word splitting. Text is pushed onto the stack with ‘print -z’ or with push-line from the line editor (see zshzle(1)). This flag is ignored when the -k or -q flags are present.
-e
-E
The input read is printed (echoed) to the standard output. If the -e flag is used, no input is assigned to the parameters.
-A The first name is taken as the name of an array and all words are assigned to it.
-c
-l
These flags are allowed only if called inside a function used for completion (specified with the -K flag to compctl). If the -c flag is given, the words of the current command are read. If the -l flag is given, the whole line is assigned as a scalar. If both flags are present, -l is used and -c is ignored.
-n Together with -c, the number of the word the cursor is on is read. With -l, the index of the character the cursor is on is read. Note that the command name is word number 1, not word 0, and that when the cursor is at the end of the line, its character index is the length of the line plus one.
-u n Input is read from file descriptor n.
-p Input is read from the coprocess.
-d delim Input is terminated by the first character of delim instead of by newline.
-t [ num ]
  Test if input is available before attempting to read. If num is present, it must begin with a digit and will be evaluated to give a number of seconds, which may be a floating point number; in this case the read times out if input is not available within this time. If num is not present, it is taken to be zero, so that read returns immediately if no input is available. If no input is available, return status 1 and do not set any variables.

This option is not available when reading from the editor buffer with -z, when called from within completion with -c or -l, with -q which clears the input queue before reading, or within zle where other mechanisms should be used to test for input.

Note that read does not attempt to alter the input processing mode. The default mode is canonical input, in which an entire line is read at a time, so usually ‘read -t’ will not read anything until an entire line has been typed. However, when reading from the terminal with -k input is processed one key at a time; in this case, only availability of the first character is tested, so that e.g. ‘read -t -k 2’ can still block on the second character. Use two instances of ‘read -t -k’ if this is not what is wanted.

If the first argument contains a ‘?’, the remainder of this word is used as a prompt on standard error when the shell is interactive.

The value (exit status) of read is 1 when an end-of-file is encountered, or when -c or -l is present and the command is not called from a compctl function, or as described for -q. Otherwise the value is 0.

The behavior of some combinations of the -k, -p, -q, -u and -z flags is undefined. Presently -q cancels all the others, -p cancels -u, -k cancels -z, and otherwise -z cancels both -p and -u.

The -c or -l flags cancel any and all of -kpquz.

readonly
  Same as typeset -r.
rehash Same as hash -r.
return [ n ]
  Causes a shell function or ‘.’ script to return to the invoking script with the return status specified by an arithmetic expression n. If n is omitted, the return status is that of the last command executed.

If return was executed from a trap in a TRAPNAL function, the effect is different for zero and non-zero return status. With zero status (or after an implicit return at the end of the trap), the shell will return to whatever it was previously processing; with a non-zero status, the shell will behave as interrupted except that the return status of the trap is retained. Note that the numeric value of the signal which caused the trap is passed as the first argument, so the statement ‘return $((128+$1))’ will return the same status as if the signal had not been trapped.

sched See the section ‘The zsh/sched Module’ in zshmodules(1).

set [ {+|-}options | {+|-}o [ option_name ] ] ... [ {+|-}A [ name ] ]
[ arg ... ]
  Set the options for the shell and/or set the positional parameters, or declare and set an array. If the -s option is given, it causes the specified arguments to be sorted before assigning them to the positional parameters (or to the array name if -A is used). With +s sort arguments in descending order. For the meaning of the other flags, see zshoptions(1). Flags may be specified by name using the -o option. If no option name is supplied with -o, the current option states are printed: see the description of setopt below for more information on the format. With +o they are printed in a form that can be used as input to the shell.

If the -A flag is specified, name is set to an array containing the given args; if no name is specified, all arrays are printed together with their values.

If +A is used and name is an array, the given arguments will replace the initial elements of that array; if no name is specified, all arrays are printed without their values.

The behaviour of arguments after -A name or +A name depends on whether the option KSH_ARRAYS is set. If it is not set, all arguments following name are treated as values for the array, regardless of their form. If the option is set, normal option processing continues at that point; only regular arguments are treated as values for the array. This means that

 
set -A array -x -- foo

sets array to ‘-x -- foo’ if KSH_ARRAYS is not set, but sets the array to foo and turns on the option ‘-x’ if it is set.

If the -A flag is not present, but there are arguments beyond the options, the positional parameters are set. If the option list (if any) is terminated by ‘--’, and there are no further arguments, the positional parameters will be unset.

If no arguments and no ‘--’ are given, then the names and values of all parameters are printed on the standard output. If the only argument is ‘+’, the names of all parameters are printed.

For historical reasons, ‘set -’ is treated as ‘set +xv’ and ‘set - args’ as ‘set +xv -- args’ when in any other emulation mode than zsh’s native mode.

setcap See the section ‘The zsh/cap Module’ in zshmodules(1).
setopt [ {+|-}options | {+|-}o option_name ] [ -m ] [ name ... ]
  Set the options for the shell. All options specified either with flags or by name are set.

If no arguments are supplied, the names of all options currently set are printed. The form is chosen so as to minimize the differences from the default options for the current emulation (the default emulation being native zsh, shown as <Z> in zshoptions(1)). Options that are on by default for the emulation are shown with the prefix no only if they are off, while other options are shown without the prefix no and only if they are on. In addition to options changed from the default state by the user, any options activated automatically by the shell (for example, SHIN_STDIN or INTERACTIVE) will be shown in the list. The format is further modified by the option KSH_OPTION_PRINT, however the rationale for choosing options with or without the no prefix remains the same in this case.

If the -m flag is given the arguments are taken as patterns (which should be quoted to protect them from filename expansion), and all options with names matching these patterns are set.

Note that a bad option name does not cause execution of subsequent shell code to be aborted; this is behaviour is different from that of ‘set -o’. This is because set is regarded as a special builtin by the POSIX standard, but setopt is not.

shift [ -p ] [ n ] [ name ... ]
  The positional parameters ${n+1} ... are renamed to $1 ..., where n is an arithmetic expression that defaults to 1. If any names are given then the arrays with these names are shifted instead of the positional parameters.

If the option -p is given arguments are instead removed (popped) from the end rather than the start of the array.

source file [ arg ... ]
  Same as ‘.’, except that the current directory is always searched and is always searched first, before directories in $path.
stat See the section ‘The zsh/stat Module’ in zshmodules(1).
suspend [ -f ]
  Suspend the execution of the shell (send it a SIGTSTP) until it receives a SIGCONT. Unless the -f option is given, this will refuse to suspend a login shell.
test [ arg ... ]
[ [ arg ... ] ]
  Like the system version of test. Added for compatibility; use conditional expressions instead (see the section ‘Conditional Expressions’). The main differences between the conditional expression syntax and the test and [ builtins are: these commands are not handled syntactically, so for example an empty variable expansion may cause an argument to be omitted; syntax errors cause status 2 to be returned instead of a shell error; and arithmetic operators expect integer arguments rather than arithmetic expressions.

The command attempts to implement POSIX and its extensions where these are specified. Unfortunately there are intrinsic ambiguities in the syntax; in particular there is no distinction between test operators and strings that resemble them. The standard attempts to resolve these for small numbers of arguments (up to four); for five or more arguments compatibility cannot be relied on. Users are urged wherever possible to use the ‘[[’ test syntax which does not have these ambiguities.

times Print the accumulated user and system times for the shell and for processes run from the shell.
trap [ arg ] [ sig ... ]
  arg is a series of commands (usually quoted to protect it from immediate evaluation by the shell) to be read and executed when the shell receives any of the signals specified by one or more sig args. Each sig can be given as a number, or as the name of a signal either with or without the string SIG in front (e.g. 1, HUP, and SIGHUP are all the same signal).

If arg is ‘-’, then the specified signals are reset to their defaults, or, if no sig args are present, all traps are reset.

If arg is an empty string, then the specified signals are ignored by the shell (and by the commands it invokes).

If arg is omitted but one or more sig args are provided (i.e. the first argument is a valid signal number or name), the effect is the same as if arg had been specified as ‘-’.

The trap command with no arguments prints a list of commands associated with each signal.

If sig is ZERR then arg will be executed after each command with a nonzero exit status. ERR is an alias for ZERR on systems that have no SIGERR signal (this is the usual case).

If sig is DEBUG then arg will be executed before each command if the option DEBUG_BEFORE_CMD is set (as it is by default), else after each command. Here, a ‘command’ is what is described as a ‘sublist’ in the shell grammar, see the section SIMPLE COMMANDS & PIPELINES in zshmisc(1). If DEBUG_BEFORE_CMD is set various additional features are available. First, it is possible to skip the next command by setting the option ERR_EXIT; see the description of the ERR_EXIT option in zshoptions(1). Also, the shell parameter ZSH_DEBUG_CMD is set to the string corresponding to the command to be executed following the trap. Note that this string is reconstructed from the internal format and may not be formatted the same way as the original text. The parameter is unset after the trap is executed.

If sig is 0 or EXIT and the trap statement is executed inside the body of a function, then the command arg is executed after the function completes. The value of $? at the start of execution is the exit status of the shell or the return status of the function exiting. If sig is 0 or EXIT and the trap statement is not executed inside the body of a function, then the command arg is executed when the shell terminates; the trap runs before any zshexit hook functions.

ZERR, DEBUG, and EXIT traps are not executed inside other traps. ZERR and DEBUG traps are kept within subshells, while other traps are reset.

Note that traps defined with the trap builtin are slightly different from those defined as ‘TRAPNAL () { ... }’, as the latter have their own function environment (line numbers, local variables, etc.) while the former use the environment of the command in which they were called. For example,

 
trap ’print $LINENO’ DEBUG

will print the line number of a command executed after it has run, while

 
TRAPDEBUG() { print $LINENO; }

will always print the number zero.

Alternative signal names are allowed as described under kill above. Defining a trap under either name causes any trap under an alternative name to be removed. However, it is recommended that for consistency users stick exclusively to one name or another.

true [ arg ... ]
  Do nothing and return an exit status of 0.
ttyctl [ -fu ]
  The -f option freezes the tty (i.e. terminal or terminal emulator), and -u unfreezes it. When the tty is frozen, no changes made to the tty settings by external programs will be honored by the shell, except for changes in the size of the screen; the shell will simply reset the settings to their previous values as soon as each command exits or is suspended. Thus, stty and similar programs have no effect when the tty is frozen. Freezing the tty does not cause the current state to be remembered: instead, it causes future changes to the state to be blocked.

Without options it reports whether the terminal is frozen or not.

Note that, regardless of whether the tty is frozen or not, the shell needs to change the settings when the line editor starts, so unfreezing the tty does not guarantee settings made on the command line are preserved. Strings of commands run between editing the command line will see a consistent tty state. See also the shell variable STTY for a means of initialising the tty before running external commands.

type [ -wfpamsS ] name ...
  Equivalent to whence -v.

typeset [ {+|-}AHUaghlmprtux ] [ {+|-}EFLRZi [ n ] ]
[ + ] [ name[=value] ... ]
typeset -T [ {+|-}Uglprux ] [ {+|-}LRZ [ n ] ]
[ + | SCALAR[=value] array[=(value ...)] [ sep ] ]
typeset -f [ {+|-}TUkmtuz ] [ + ] [ name ... ]
  Set or display attributes and values for shell parameters.

A parameter is created for each name that does not already refer to one. When inside a function, a new parameter is created for every name (even those that already exist), and is unset again when the function completes. See ‘Local Parameters’ in zshparam(1). The same rules apply to special shell parameters, which retain their special attributes when made local.

For each name=value assignment, the parameter name is set to value. All forms of the command handle scalar assignment.

If any of the reserved words declare, export, float, integer, local, readonly or typeset is matched when the line is parsed (N.B. not when it is executed) the shell will try to parse arguments as assignments, except that the ‘+=’ syntax and the GLOB_ASSIGN option are not supported. This has two major differences from normal command line argument parsing: array assignment is possible, and scalar values after = are not split further into words even if expanded (regardless of the setting of the KSH_TYPESET option; this option is obsolete). Here is an example:

 
# Reserved word parsing
typeset svar=$(echo one word) avar=(several words)

The above creates a scalar parameter svar and an array parameter avar as if the assignments had been

 
svar="one word"
avar=(several words)

On the other hand:

 
# Normal builtin interface
builtin typeset svar=$(echo two words)

The builtin keyword causes the above to use the standard builtin interface to typeset in which argument parsing is perfomed in the same way as for other commands. This example creates a scalar svar containing the value two and another scalar parameter words with no value. An array value in this case would either cause an error or be treated as an obscure set of glob qualifiers.

Arbitrary arguments are allowed if they take the form of assignments after command line expansion; however, these only perform scalar assignment:

 
var=’svar=val’
typeset $var

The above sets the scalar parameter svar to the value val. Parentheses around the value within var would not cause array assignment as they will be treated as ordinary characters when $var is substituted. Any non-trivial expansion in the name part of the assignment causes the argument to be treated in this fashion:

 
typeset {var1,var2,var3}=name

The above syntax is valid, and has the expected effect of setting the three parameters to the same value, but the command line is parsed as a set of three normal command line arguments to typeset after expansion. Hence it is not possible to assign to multiple arrays by this means.

Note that each interface to any of the commands my be disabled separately. For example, ‘disable -r typeset’ disables the reserved word interface to typeset, exposing the builtin interface, while ‘disable typeset’ disables the builtin.

If the shell option TYPESET_SILENT is not set, for each remaining name that refers to a parameter that is already set, the name and value of the parameter are printed in the form of an assignment. Nothing is printed for newly-created parameters, or when any attribute flags listed below are given along with the name. Using ‘+’ instead of minus to introduce an attribute turns it off.

If no name is present, the names and values of all parameters are printed. In this case the attribute flags restrict the display to only those parameters that have the specified attributes, and using ‘+’ rather than ‘-’ to introduce the flag suppresses printing of the values of parameters when there is no parameter name.

If no attribute flags are given, and either no name arguments are present or the flag +m is used, then each parameter name printed is preceded by a list of the attributes of that parameter (array, association, exported, float, integer, readonly, or undefined for autoloaded parameters not yet loaded). If +m is used with attribute flags, and all those flags are introduced with +, the matching parameter names are printed but their values are not.

The following control flags change the behavior of typeset:

+ If ‘+’ appears by itself in a separate word as the last option, then the names of all parameters (functions with -f) are printed, but the values (function bodies) are not. No name arguments may appear, and it is an error for any other options to follow ‘+’. The effect of ‘+’ is as if all attribute flags which precede it were given with a ‘+’ prefix. For example, ‘typeset -U +’ is equivalent to ‘typeset +U’ and displays the names of all arrays having the uniqueness attribute, whereas ‘typeset -f -U +’ displays the names of all autoloadable functions. If + is the only option, then type information (array, readonly, etc.) is also printed for each parameter, in the same manner as ‘typeset +m "*"’.
-g The -g (global) means that any resulting parameter will not be restricted to local scope. Note that this does not necessarily mean that the parameter will be global, as the flag will apply to any existing parameter (even if unset) from an enclosing function. This flag does not affect the parameter after creation, hence it has no effect when listing existing parameters, nor does the flag +g have any effect except in combination with -m (see below).
-m If the -m flag is given the name arguments are taken as patterns (use quoting to prevent these from being interpreted as file patterns). With no attribute flags, all parameters (or functions with the -f flag) with matching names are printed (the shell option TYPESET_SILENT is not used in this case).

If the +g flag is combined with -m, a new local parameter is created for every matching parameter that is not already local. Otherwise -m applies all other flags or assignments to the existing parameters.

Except when assignments are made with name=value, using +m forces the matching parameters and their attributes to be printed, even inside a function. Note that -m is ignored if no patterns are given, so ‘typeset -m’ displays attributes but ‘typeset -a +m’ does not.

-p If the -p option is given, parameters and values are printed in the form of a typeset command and an assignment (which will be printed separately for arrays and associative arrays), regardless of other flags and options. Note that the -H flag on parameters is respected; no value will be shown for these parameters.

As the intention of this option is to produce output that can restore the current state, readonly specials (whose values cannot be changed) are not shown and assignments to arrays are shown before the typeset rendering the array readonly.

-T [ scalar[=value] array[=(value ...)] [ sep ] ]
  This flag has a different meaning when used with -f; see below. Otherwise the -T option requires zero, two, or three arguments to be present. With no arguments, the list of parameters created in this fashion is shown. With two or three arguments, the first two are the name of a scalar and of an array parameter (in that order) that will be tied together in the manner of $PATH and $path. The optional third argument is a single-character separator which will be used to join the elements of the array to form the scalar; if absent, a colon is used, as with $PATH. Only the first character of the separator is significant; any remaining characters are ignored. Multibyte characters are not yet supported.

Only one of the scalar and array parameters may be assigned an initial value (the restrictions on assignment forms described above also apply).

Both the scalar and the array may be manipulated as normal. If one is unset, the other will automatically be unset too. There is no way of untying the variables without unsetting them, nor of converting the type of one of them with another typeset command; +T does not work, assigning an array to scalar is an error, and assigning a scalar to array sets it to be a single-element array.

Note that both ‘typeset -xT ...’ and ‘export -T ...’ work, but only the scalar will be marked for export. Setting the value using the scalar version causes a split on all separators (which cannot be quoted). It is possible to apply -T to two previously tied variables but with a different separator character, in which case the variables remain joined as before but the separator is changed.

Attribute flags that transform the final value (-L, -R, -Z, -l, -u) are only applied to the expanded value at the point of a parameter expansion expression using ‘$’. They are not applied when a parameter is retrieved internally by the shell for any purpose.
The following attribute flags may be specified:
-A The names refer to associative array parameters; see ‘Array Parameters’ in zshparam(1).
-L [ n ] Left justify and remove leading blanks from the value when the parameter is expanded. If n is nonzero, it defines the width of the field. If n is zero, the width is determined by the width of the value of the first assignment. In the case of numeric parameters, the length of the complete value assigned to the parameter is used to determine the width, not the value that would be output.

The width is the count of characters, which may be multibyte characters if the MULTIBYTE option is in effect. Note that the screen width of the character is not taken into account; if this is required, use padding with parameter expansion flags ${(ml...)...} as described in ‘Parameter Expansion Flags’ in zshexpn(1).

When the parameter is expanded, it is filled on the right with blanks or truncated if necessary to fit the field. Note truncation can lead to unexpected results with numeric parameters. Leading zeros are removed if the -Z flag is also set.

-R [ n ] Similar to -L, except that right justification is used; when the parameter is expanded, the field is left filled with blanks or truncated from the end. May not be combined with the -Z flag.
-U For arrays (but not for associative arrays), keep only the first occurrence of each duplicated value. This may also be set for colon-separated special parameters like PATH or FIGNORE, etc. This flag has a different meaning when used with -f; see below.
-Z [ n ] Specially handled if set along with the -L flag. Otherwise, similar to -R, except that leading zeros are used for padding instead of blanks if the first non-blank character is a digit. Numeric parameters are specially handled: they are always eligible for padding with zeroes, and the zeroes are inserted at an appropriate place in the output.
-a The names refer to array parameters. An array parameter may be created this way, but it may not be assigned to in the typeset statement. When displaying, both normal and associative arrays are shown.
-f The names refer to functions rather than parameters. No assignments can be made, and the only other valid flags are -t, -T, -k, -u, -U and -z. The flag -t turns on execution tracing for this function; the flag -T does the same, but turns off tracing on any function called from the present one, unless that function also has the -t or -T flag. The -u and -U flags cause the function to be marked for autoloading; -U also causes alias expansion to be suppressed when the function is loaded. See the description of the ‘autoload’ builtin for details.

Note that the builtin functions provides the same basic capabilities as typeset -f but gives access to a few extra options.

-h Hide: only useful for special parameters (those marked ‘<S>’ in the table in zshparam(1)), and for local parameters with the same name as a special parameter, though harmless for others. A special parameter with this attribute will not retain its special effect when made local. Thus after ‘typeset -h PATH’, a function containing ‘typeset PATH’ will create an ordinary local parameter without the usual behaviour of PATH. Alternatively, the local parameter may itself be given this attribute; hence inside a function ‘typeset -h PATH’ creates an ordinary local parameter and the special PATH parameter is not altered in any way. It is also possible to create a local parameter using ‘typeset +h special’, where the local copy of special will retain its special properties regardless of having the -h attribute. Global special parameters loaded from shell modules (currently those in zsh/mapfile and zsh/parameter) are automatically given the -h attribute to avoid name clashes.
-H Hide value: specifies that typeset will not display the value of the parameter when listing parameters; the display for such parameters is always as if the ‘+’ flag had been given. Use of the parameter is in other respects normal, and the option does not apply if the parameter is specified by name, or by pattern with the -m option. This is on by default for the parameters in the zsh/parameter and zsh/mapfile modules. Note, however, that unlike the -h flag this is also useful for non-special parameters.
-i [ n ] Use an internal integer representation. If n is nonzero it defines the output arithmetic base, otherwise it is determined by the first assignment. Bases from 2 to 36 inclusive are allowed.
-E [ n ] Use an internal double-precision floating point representation. On output the variable will be converted to scientific notation. If n is nonzero it defines the number of significant figures to display; the default is ten.
-F [ n ] Use an internal double-precision floating point representation. On output the variable will be converted to fixed-point decimal notation. If n is nonzero it defines the number of digits to display after the decimal point; the default is ten.
-l Convert the result to lower case whenever the parameter is expanded. The value is not converted when assigned.
-r The given names are marked readonly. Note that if name is a special parameter, the readonly attribute can be turned on, but cannot then be turned off.

If the POSIX_BUILTINS option is set, the readonly attribute is more restrictive: unset variables can be marked readonly and cannot then be set; furthermore, the readonly attribute cannot be removed from any variable. Note that in zsh (unlike other shells) it is still possible to create a local variable of the same name as this is considered a different variable (though this variable, too, can be marked readonly).

-t Tags the named parameters. Tags have no special meaning to the shell. This flag has a different meaning when used with -f; see above.
-u Convert the result to upper case whenever the parameter is expanded. The value is not converted when assigned. This flag has a different meaning when used with -f; see above.
-x Mark for automatic export to the environment of subsequently executed commands. If the option GLOBAL_EXPORT is set, this implies the option -g, unless +g is also explicitly given; in other words the parameter is not made local to the enclosing function. This is for compatibility with previous versions of zsh.

ulimit [ -HSa ] [ { -bcdfiklmnpqrsTtvwx | -N resource } [ limit ] ... ]
  Set or display resource limits of the shell and the processes started by the shell. The value of limit can be a number in the unit specified below or one of the values ‘unlimited’, which removes the limit on the resource, or ‘hard’, which uses the current value of the hard limit on the resource.

By default, only soft limits are manipulated. If the -H flag is given use hard limits instead of soft limits. If the -S flag is given together with the -H flag set both hard and soft limits.

If no options are used, the file size limit (-f) is assumed.

If limit is omitted the current value of the specified resources are printed. When more than one resource value is printed, the limit name and unit is printed before each value.

When looping over multiple resources, the shell will abort immediately if it detects a badly formed argument. However, if it fails to set a limit for some other reason it will continue trying to set the remaining limits.

Not all the following resources are supported on all systems. Running ulimit -a will show which are supported.

-a Lists all of the current resource limits.
-b Socket buffer size in bytes (N.B. not kilobytes)
-c 512-byte blocks on the size of core dumps.
-d Kilobytes on the size of the data segment.
-f 512-byte blocks on the size of files written.
-i The number of pending signals.
-k The number of kqueues allocated.
-l Kilobytes on the size of locked-in memory.
-m Kilobytes on the size of physical memory.
-n open file descriptors.
-p The number of pseudo-terminals.
-q Bytes in POSIX message queues.
-r Maximum real time priority. On some systems where this is not available, such as NetBSD, this has the same effect as -T for compatibility with sh.
-s Kilobytes on the size of the stack.
-T The number of simultaneous threads available to the user.
-t CPU seconds to be used.
-u The number of processes available to the user.
-v Kilobytes on the size of virtual memory. On some systems this refers to the limit called ‘address space’.
-w Kilobytes on the size of swapped out memory.
-x The number of locks on files.
A resource may also be specified by integer in the form ‘-N resource’, where resource corresponds to the integer defined for the resource by the operating system. This may be used to set the limits for resources known to the shell which do not correspond to option letters. Such limits will be shown by number in the output of ‘ulimit -a’.

The number may alternatively be out of the range of limits compiled into the shell. The shell will try to read or write the limit anyway, and will report an error if this fails.

umask [ -S ] [ mask ]
  The umask is set to mask. mask can be either an octal number or a symbolic value as described in chmod(1). If mask is omitted, the current value is printed. The -S option causes the mask to be printed as a symbolic value. Otherwise, the mask is printed as an octal number. Note that in the symbolic form the permissions you specify are those which are to be allowed (not denied) to the users specified.
unalias [ -ams ] name ...
  Removes aliases. This command works the same as unhash -a, except that the -a option removes all regular or global aliases, or with -s all suffix aliases: in this case no name arguments may appear. The options -m (remove by pattern) and -s without -a (remove listed suffix aliases) behave as for unhash -a. Note that the meaning of -a is different between unalias and unhash.
unfunction
  Same as unhash -f.
unhash [ -adfms ] name ...
  Remove the element named name from an internal hash table. The default is remove elements from the command hash table. The -a option causes unhash to remove regular or global aliases; note when removing a global aliases that the argument must be quoted to prevent it from being expanded before being passed to the command. The -s option causes unhash to remove suffix aliases. The -f option causes unhash to remove shell functions. The -d options causes unhash to remove named directories. If the -m flag is given the arguments are taken as patterns (should be quoted) and all elements of the corresponding hash table with matching names will be removed.
unlimit [ -hs ] resource ...
  The resource limit for each resource is set to the hard limit. If the -h flag is given and the shell has appropriate privileges, the hard resource limit for each resource is removed. The resources of the shell process are only changed if the -s flag is given.

The unlimit command is not made available by default when the shell starts in a mode emulating another shell. It can be made available with the command ‘zmodload -F zsh/rlimits b:unlimit’.

unset [ -fmv ] name ...
  Each named parameter is unset. Local parameters remain local even if unset; they appear unset within scope, but the previous value will still reappear when the scope ends.

Individual elements of associative array parameters may be unset by using subscript syntax on name, which should be quoted (or the entire command prefixed with noglob) to protect the subscript from filename generation.

If the -m flag is specified the arguments are taken as patterns (should be quoted) and all parameters with matching names are unset. Note that this cannot be used when unsetting associative array elements, as the subscript will be treated as part of the pattern.

The -v flag specifies that name refers to parameters. This is the default behaviour.

unset -f is equivalent to unfunction.

unsetopt [ {+|-}options | {+|-}o option_name ] [ name ... ]
  Unset the options for the shell. All options specified either with flags or by name are unset. If no arguments are supplied, the names of all options currently unset are printed. If the -m flag is given the arguments are taken as patterns (which should be quoted to preserve them from being interpreted as glob patterns), and all options with names matching these patterns are unset.
vared See the section ‘Zle Builtins’ in zshzle(1).
wait [ job ... ]
  Wait for the specified jobs or processes. If job is not given then all currently active child processes are waited for. Each job can be either a job specification or the process ID of a job in the job table. The exit status from this command is that of the job waited for.

It is possible to wait for recent processes (specified by process ID, not by job) that were running in the background even if the process has exited. Typically the process ID will be recorded by capturing the value of the variable $! immediately after the process has been started. There is a limit on the number of process IDs remembered by the shell; this is given by the value of the system configuration parameter CHILD_MAX. When this limit is reached, older process IDs are discarded, least recently started processes first.

Note there is no protection against the process ID wrapping, i.e. if the wait is not executed soon enough there is a chance the process waited for is the wrong one. A conflict implies both process IDs have been generated by the shell, as other processes are not recorded, and that the user is potentially interested in both, so this problem is intrinsic to process IDs.

whence [ -vcwfpamsS ] [ -x num ] name ...
  For each name, indicate how it would be interpreted if used as a command name.

whence is most useful when name is only the last path component of a command, i.e. does not include a ‘/’; in particular, pattern matching only succeeds if just the non-directory component of the command is passed.

-v Produce a more verbose report.
-c Print the results in a csh-like format. This takes precedence over -v.
-w For each name, print ‘name: word’ where word is one of alias, builtin, command, function, hashed, reserved or none, according as name corresponds to an alias, a built-in command, an external command, a shell function, a command defined with the hash builtin, a reserved word, or is not recognised. This takes precedence over -v and -c.
-f Causes the contents of a shell function to be displayed, which would otherwise not happen unless the -c flag were used.
-p Do a path search for name even if it is an alias, reserved word, shell function or builtin.
-a Do a search for all occurrences of name throughout the command path. Normally only the first occurrence is printed.
-m The arguments are taken as patterns (pattern characters should be quoted), and the information is displayed for each command matching one of these patterns.
-s If a pathname contains symlinks, print the symlink-free pathname as well.
-S As -s, but if the pathname had to be resolved by following multiple symlinks, the intermediate steps are printed, too. The symlink resolved at each step might be anywhere in the path.
-x num Expand tabs when outputting shell functions using the -c option. This has the same effect as the -x option to the functions builtin.

where [ -wpmsS ] [ -x num ] name ...
  Equivalent to whence -ca.
which [ -wpamsS ] [ -x num ] name ...
  Equivalent to whence -c.
zcompile [ -U ] [ -z | -k ] [ -R | -M ] file [ name ... ]
zcompile -ca [ -m ] [ -R | -M ] file [ name ... ]
zcompile -t file [ name ... ]
  This builtin command can be used to compile functions or scripts, storing the compiled form in a file, and to examine files containing the compiled form. This allows faster autoloading of functions and sourcing of scripts by avoiding parsing of the text when the files are read.

The first form (without the -c, -a or -t options) creates a compiled file. If only the file argument is given, the output file has the name ‘file.zwc’ and will be placed in the same directory as the file. The shell will load the compiled file instead of the normal function file when the function is autoloaded; see the section ‘Autoloading Functions’ in zshmisc(1) for a description of how autoloaded functions are searched. The extension .zwc stands for ‘zsh word code’.

If there is at least one name argument, all the named files are compiled into the output file given as the first argument. If file does not end in .zwc, this extension is automatically appended. Files containing multiple compiled functions are called ‘digest’ files, and are intended to be used as elements of the FPATH/fpath special array.

The second form, with the -c or -a options, writes the compiled definitions for all the named functions into file. For -c, the names must be functions currently defined in the shell, not those marked for autoloading. Undefined functions that are marked for autoloading may be written by using the -a option, in which case the fpath is searched and the contents of the definition files for those functions, if found, are compiled into file. If both -c and -a are given, names of both defined functions and functions marked for autoloading may be given. In either case, the functions in files written with the -c or -a option will be autoloaded as if the KSH_AUTOLOAD option were unset.

The reason for handling loaded and not-yet-loaded functions with different options is that some definition files for autoloading define multiple functions, including the function with the same name as the file, and, at the end, call that function. In such cases the output of ‘zcompile -c’ does not include the additional functions defined in the file, and any other initialization code in the file is lost. Using ‘zcompile -a’ captures all this extra information.

If the -m option is combined with -c or -a, the names are used as patterns and all functions whose names match one of these patterns will be written. If no name is given, the definitions of all functions currently defined or marked as autoloaded will be written.

Note the second form cannot be used for compiling functions that include redirections as part of the definition rather than within the body of the function; for example

 
fn1() { { ... } >~/logfile }

can be compiled but

 
fn1() { ... } >~/logfile

cannot. It is possible to use the first form of zcompile to compile autoloadable functions that include the full function definition instead of just the body of the function.

The third form, with the -t option, examines an existing compiled file. Without further arguments, the names of the original files compiled into it are listed. The first line of output shows the version of the shell which compiled the file and how the file will be used (i.e. by reading it directly or by mapping it into memory). With arguments, nothing is output and the return status is set to zero if definitions for all names were found in the compiled file, and non-zero if the definition for at least one name was not found.

Other options:

-U Aliases are not expanded when compiling the named files.
-R When the compiled file is read, its contents are copied into the shell’s memory, rather than memory-mapped (see -M). This happens automatically on systems that do not support memory mapping.

When compiling scripts instead of autoloadable functions, it is often desirable to use this option; otherwise the whole file, including the code to define functions which have already been defined, will remain mapped, consequently wasting memory.

-M The compiled file is mapped into the shell’s memory when read. This is done in such a way that multiple instances of the shell running on the same host will share this mapped file. If neither -R nor -M is given, the zcompile builtin decides what to do based on the size of the compiled file.
-k
-z
These options are used when the compiled file contains functions which are to be autoloaded. If -z is given, the function will be autoloaded as if the KSH_AUTOLOAD option is not set, even if it is set at the time the compiled file is read, while if the -k is given, the function will be loaded as if KSH_AUTOLOAD is set. These options also take precedence over any -k or -z options specified to the autoload builtin. If neither of these options is given, the function will be loaded as determined by the setting of the KSH_AUTOLOAD option at the time the compiled file is read.

These options may also appear as many times as necessary between the listed names to specify the loading style of all following functions, up to the next -k or -z.

The created file always contains two versions of the compiled format, one for big-endian machines and one for small-endian machines. The upshot of this is that the compiled file is machine independent and if it is read or mapped, only one half of the file is actually used (and mapped).

zformat
  See the section ‘The zsh/zutil Module’ in zshmodules(1).
zftp See the section ‘The zsh/zftp Module’ in zshmodules(1).
zle See the section ‘Zle Builtins’ in zshzle(1).
zmodload [ -dL ] [ ... ]
zmodload -F [ -alLme -P param ] module [ [+-]feature ... ]
zmodload -e [ -A ] [ ... ]
zmodload [ -a [ -bcpf [ -I ] ] ] [ -iL ] ...
zmodload -u [ -abcdpf [ -I ] ] [ -iL ] ...
zmodload -A [ -L ] [ modalias[=module] ... ]
zmodload -R modalias ...
  Performs operations relating to zsh’s loadable modules. Loading of modules while the shell is running (‘dynamical loading’) is not available on all operating systems, or on all installations on a particular operating system, although the zmodload command itself is always available and can be used to manipulate modules built into versions of the shell executable without dynamical loading.

Without arguments the names of all currently loaded binary modules are printed. The -L option causes this list to be in the form of a series of zmodload commands. Forms with arguments are:

zmodload [ -i ] name ...
zmodload -u [ -i ] name ...
  In the simplest case, zmodload loads a binary module. The module must be in a file with a name consisting of the specified name followed by a standard suffix, usually ‘.so’ (‘.sl’ on HPUX). If the module to be loaded is already loaded the duplicate module is ignored. If zmodload detects an inconsistency, such as an invalid module name or circular dependency list, the current code block is aborted. Hence ‘zmodload module 2>/dev/null’ is sufficient to test whether a module is available. If it is available, the module is loaded if necessary, while if it is not available, non-zero status is silently returned. The option -i is accepted for compatibility but has no effect.

The named module is searched for in the same way a command is, using $module_path instead of $path. However, the path search is performed even when the module name contains a ‘/’, which it usually does. There is no way to prevent the path search.

If the module supports features (see below), zmodload tries to enable all features when loading a module. If the module was successfully loaded but not all features could be enabled, zmodload returns status 2.

With -u, zmodload unloads modules. The same name must be given that was given when the module was loaded, but it is not necessary for the module to exist in the file system. The -i option suppresses the error if the module is already unloaded (or was never loaded).

Each module has a boot and a cleanup function. The module will not be loaded if its boot function fails. Similarly a module can only be unloaded if its cleanup function runs successfully.

zmodload -F [ -almLe -P param ] module [ [+-]feature ... ]
  zmodload -F allows more selective control over the features provided by modules. With no options apart from -F, the module named module is loaded, if it was not already loaded, and the list of features is set to the required state. If no features are specified, the module is loaded, if it was not already loaded, but the state of features is unchanged. Each feature may be preceded by a + to turn the feature on, or - to turn it off; the + is assumed if neither character is present. Any feature not explicitly mentioned is left in its current state; if the module was not previously loaded this means any such features will remain disabled. The return status is zero if all features were set, 1 if the module failed to load, and 2 if some features could not be set (for example, a parameter couldn’t be added because there was a different parameter of the same name) but the module was loaded.

The standard features are builtins, conditions, parameters and math functions; these are indicated by the prefix ‘b:’, ‘c:’ (‘C:’ for an infix condition), ‘p:’ and ‘f:’, respectively, followed by the name that the corresponding feature would have in the shell. For example, ‘b:strftime’ indicates a builtin named strftime and p:EPOCHSECONDS indicates a parameter named EPOCHSECONDS. The module may provide other (‘abstract’) features of its own as indicated by its documentation; these have no prefix.

With -l or -L, features provided by the module are listed. With -l alone, a list of features together with their states is shown, one feature per line. With -L alone, a zmodload -F command that would cause enabled features of the module to be turned on is shown. With -lL, a zmodload -F command that would cause all the features to be set to their current state is shown. If one of these combinations is given with the option -P param then the parameter param is set to an array of features, either features together with their state or (if -L alone is given) enabled features.

With the option -L the module name may be omitted; then a list of all enabled features for all modules providing features is printed in the form of zmodload -F commands. If -l is also given, the state of both enabled and disabled features is output in that form.

A set of features may be provided together with -l or -L and a module name; in that case only the state of those features is considered. Each feature may be preceded by + or - but the character has no effect. If no set of features is provided, all features are considered.

With -e, the command first tests that the module is loaded; if it is not, status 1 is returned. If the module is loaded, the list of features given as an argument is examined. Any feature given with no prefix is simply tested to see if the module provides it; any feature given with a prefix + or - is tested to see if is provided and in the given state. If the tests on all features in the list succeed, status 0 is returned, else status 1.

With -m, each entry in the given list of features is taken as a pattern to be matched against the list of features provided by the module. An initial + or - must be given explicitly. This may not be combined with the -a option as autoloads must be specified explicitly.

With -a, the given list of features is marked for autoload from the specified module, which may not yet be loaded. An optional + may appear before the feature name. If the feature is prefixed with -, any existing autoload is removed. The options -l and -L may be used to list autoloads. Autoloading is specific to individual features; when the module is loaded only the requested feature is enabled. Autoload requests are preserved if the module is subsequently unloaded until an explicit ‘zmodload -Fa module -feature’ is issued. It is not an error to request an autoload for a feature of a module that is already loaded.

When the module is loaded each autoload is checked against the features actually provided by the module; if the feature is not provided the autoload request is deleted. A warning message is output; if the module is being loaded to provide a different feature, and that autoload is successful, there is no effect on the status of the current command. If the module is already loaded at the time when zmodload -Fa is run, an error message is printed and status 1 returned.

zmodload -Fa can be used with the -l, -L, -e and -P options for listing and testing the existence of autoloadable features. In this case -l is ignored if -L is specified. zmodload -FaL with no module name lists autoloads for all modules.

Note that only standard features as described above can be autoloaded; other features require the module to be loaded before enabling.

zmodload -d [ -L ] [ name ]
zmodload -d name dep ...
zmodload -ud name [ dep ... ]
  The -d option can be used to specify module dependencies. The modules named in the second and subsequent arguments will be loaded before the module named in the first argument.

With -d and one argument, all dependencies for that module are listed. With -d and no arguments, all module dependencies are listed. This listing is by default in a Makefile-like format. The -L option changes this format to a list of zmodload -d commands.

If -d and -u are both used, dependencies are removed. If only one argument is given, all dependencies for that module are removed.

zmodload -ab [ -L ]
zmodload -ab [ -i ] name [ builtin ... ]
zmodload -ub [ -i ] builtin ...
  The -ab option defines autoloaded builtins. It defines the specified builtins. When any of those builtins is called, the module specified in the first argument is loaded and all its features are enabled (for selective control of features use ‘zmodload -F -a’ as described above). If only the name is given, one builtin is defined, with the same name as the module. -i suppresses the error if the builtin is already defined or autoloaded, but not if another builtin of the same name is already defined.

With -ab and no arguments, all autoloaded builtins are listed, with the module name (if different) shown in parentheses after the builtin name. The -L option changes this format to a list of zmodload -a commands.

If -b is used together with the -u option, it removes builtins previously defined with -ab. This is only possible if the builtin is not yet loaded. -i suppresses the error if the builtin is already removed (or never existed).

Autoload requests are retained if the module is subsequently unloaded until an explicit ‘zmodload -ub builtin’ is issued.

zmodload -ac [ -IL ]
zmodload -ac [ -iI ] name [ cond ... ]
zmodload -uc [ -iI ] cond ...
  The -ac option is used to define autoloaded condition codes. The cond strings give the names of the conditions defined by the module. The optional -I option is used to define infix condition names. Without this option prefix condition names are defined.

If given no condition names, all defined names are listed (as a series of zmodload commands if the -L option is given).

The -uc option removes definitions for autoloaded conditions.

zmodload -ap [ -L ]
zmodload -ap [ -i ] name [ parameter ... ]
zmodload -up [ -i ] parameter ...
  The -p option is like the -b and -c options, but makes zmodload work on autoloaded parameters instead.
zmodload -af [ -L ]
zmodload -af [ -i ] name [ function ... ]
zmodload -uf [ -i ] function ...
  The -f option is like the -b, -p, and -c options, but makes zmodload work on autoloaded math functions instead.
zmodload -a [ -L ]
zmodload -a [ -i ] name [ builtin ... ]
zmodload -ua [ -i ] builtin ...
  Equivalent to -ab and -ub.
zmodload -e [ -A ] [ string ... ]
  The -e option without arguments lists all loaded modules; if the -A option is also given, module aliases corresponding to loaded modules are also shown. If arguments are provided, nothing is printed; the return status is set to zero if all strings given as arguments are names of loaded modules and to one if at least on string is not the name of a loaded module. This can be used to test for the availability of things implemented by modules. In this case, any aliases are automatically resolved and the -A flag is not used.
zmodload -A [ -L ] [ modalias[=module] ... ]
  For each argument, if both modalias and module are given, define modalias to be an alias for the module module. If the module modalias is ever subsequently requested, either via a call to zmodload or implicitly, the shell will attempt to load module instead. If module is not given, show the definition of modalias. If no arguments are given, list all defined module aliases. When listing, if the -L flag was also given, list the definition as a zmodload command to recreate the alias.

The existence of aliases for modules is completely independent of whether the name resolved is actually loaded as a module: while the alias exists, loading and unloading the module under any alias has exactly the same effect as using the resolved name, and does not affect the connection between the alias and the resolved name which can be removed either by zmodload -R or by redefining the alias. Chains of aliases (i.e. where the first resolved name is itself an alias) are valid so long as these are not circular. As the aliases take the same format as module names, they may include path separators: in this case, there is no requirement for any part of the path named to exist as the alias will be resolved first. For example, ‘any/old/alias’ is always a valid alias.

Dependencies added to aliased modules are actually added to the resolved module; these remain if the alias is removed. It is valid to create an alias whose name is one of the standard shell modules and which resolves to a different module. However, if a module has dependencies, it will not be possible to use the module name as an alias as the module will already be marked as a loadable module in its own right.

Apart from the above, aliases can be used in the zmodload command anywhere module names are required. However, aliases will not be shown in lists of loaded modules with a bare ‘zmodload’.

zmodload -R modalias ...
  For each modalias argument that was previously defined as a module alias via zmodload -A, delete the alias. If any was not defined, an error is caused and the remainder of the line is ignored.
Note that zsh makes no distinction between modules that were linked into the shell and modules that are loaded dynamically. In both cases this builtin command has to be used to make available the builtins and other things defined by modules (unless the module is autoloaded on these definitions). This is true even for systems that don’t support dynamic loading of modules.

zparseopts
  See the section ‘The zsh/zutil Module’ in zshmodules(1).
zprof See the section ‘The zsh/zprof Module’ in zshmodules(1).
zpty See the section ‘The zsh/zpty Module’ in zshmodules(1).
zregexparse
  See the section ‘The zsh/zutil Module’ in zshmodules(1).
zsocket
  See the section ‘The zsh/net/socket Module’ in zshmodules(1).
zstyle See the section ‘The zsh/zutil Module’ in zshmodules(1).
ztcp See the section ‘The zsh/net/tcp Module’ in zshmodules(1).

NAME

zshzle - zsh command line editor

DESCRIPTION

If the ZLE option is set (which it is by default in interactive shells) and the shell input is attached to the terminal, the user is able to edit command lines.

There are two display modes. The first, multiline mode, is the default. It only works if the TERM parameter is set to a valid terminal type that can move the cursor up. The second, single line mode, is used if TERM is invalid or incapable of moving the cursor up, or if the SINGLE_LINE_ZLE option is set. This mode is similar to ksh, and uses no termcap sequences. If TERM is "emacs", the ZLE option will be unset by default.

The parameters BAUD, COLUMNS, and LINES are also used by the line editor. See Parameters Used By The Shell in zshparam(1).

The parameter zle_highlight is also used by the line editor; see Character Highlighting below. Highlighting of special characters and the region between the cursor and the mark (as set with set-mark-command in Emacs mode, or by visual-mode in Vi mode) is enabled by default; consult this reference for more information. Irascible conservatives will wish to know that all highlighting may be disabled by the following setting:

zle_highlight=(none)

In many places, references are made to the numeric argument. This can by default be entered in emacs mode by holding the alt key and typing a number, or pressing escape before each digit, and in vi command mode by typing the number before entering a command. Generally the numeric argument causes the next command entered to be repeated the specified number of times, unless otherwise noted below. See also the Arguments subsection of the Widgets section for some other ways the numeric argument can be modified. The default bindings mentioned here use the digit-argument widget.

KEYMAPS

A keymap in ZLE contains a set of bindings between key sequences and ZLE commands. The empty key sequence cannot be bound.

There can be any number of keymaps at any time, and each keymap has one or more names. If all of a keymap’s names are deleted, it disappears. bindkey can be used to manipulate keymap names.

Initially, there are eight keymaps:

emacs EMACS emulation
viins vi emulation - insert mode
vicmd vi emulation - command mode
viopp vi emulation - operator pending
visual vi emulation - selection active
isearch
  incremental search mode
command
  read a command name
.safe fallback keymap
The ‘.safe’ keymap is special. It can never be altered, and the name can never be removed. However, it can be linked to other names, which can be removed. In the future other special keymaps may be added; users should avoid using names beginning with ‘.’ for their own keymaps.

In addition to these names, either ‘emacs’ or ‘viins’ is also linked to the name ‘main’. If one of the VISUAL or EDITOR environment variables contain the string ‘vi’ when the shell starts up then it will be ‘viins’, otherwise it will be ‘emacs’. bindkey’s -e and -v options provide a convenient way to override this default choice.

When the editor starts up, it will select the ‘main’ keymap. If that keymap doesn’t exist, it will use ‘.safe’ instead.

In the ‘.safe’ keymap, each single key is bound to self-insert, except for ^J (line feed) and ^M (return) which are bound to accept-line. This is deliberately not pleasant to use; if you are using it, it means you deleted the main keymap, and you should put it back.

    Reading Commands

When ZLE is reading a command from the terminal, it may read a sequence that is bound to some command and is also a prefix of a longer bound string. In this case ZLE will wait a certain time to see if more characters are typed, and if not (or they don’t match any longer string) it will execute the binding. This timeout is defined by the KEYTIMEOUT parameter; its default is 0.4 sec. There is no timeout if the prefix string is not itself bound to a command.

The key timeout is also applied when ZLE is reading the bytes from a multibyte character string when it is in the appropriate mode. (This requires that the shell was compiled with multibyte mode enabled; typically also the locale has characters with the UTF-8 encoding, although any multibyte encoding known to the operating system is supported.) If the second or a subsequent byte is not read within the timeout period, the shell acts as if ? were typed and resets the input state.

As well as ZLE commands, key sequences can be bound to other strings, by using ‘bindkey -s’. When such a sequence is read, the replacement string is pushed back as input, and the command reading process starts again using these fake keystrokes. This input can itself invoke further replacement strings, but in order to detect loops the process will be stopped if there are twenty such replacements without a real command being read.

A key sequence typed by the user can be turned into a command name for use in user-defined widgets with the read-command widget, described in the subsection ‘Miscellaneous’ of the section ‘Standard Widgets’ below.

    Local Keymaps

While for normal editing a single keymap is used exclusively, in many modes a local keymap allows for some keys to be customised. For example, in an incremental search mode, a binding in the isearch keymap will override a binding in the main keymap but all keys that are not overridden can still be used.

If a key sequence is defined in a local keymap, it will hide a key sequence in the global keymap that is a prefix of that sequence. An example of this occurs with the binding of iw in viopp as this hides the binding of i in vicmd. However, a longer sequence in the global keymap that shares the same prefix can still apply so for example the binding of ^Xa in the global keymap will be unaffected by the binding of ^Xb in the local keymap.

ZLE BUILTINS

The ZLE module contains three related builtin commands. The bindkey command manipulates keymaps and key bindings; the vared command invokes ZLE on the value of a shell parameter; and the zle command manipulates editing widgets and allows command line access to ZLE commands from within shell functions.

bindkey [ options ] -l [ -L ] [ keymap ... ]
bindkey [ options ] -d
bindkey [ options ] -D keymap ...
bindkey [ options ] -A old-keymap new-keymap
bindkey [ options ] -N new-keymap [ old-keymap ]
bindkey [ options ] -m
bindkey [ options ] -r in-string ...
bindkey [ options ] -s in-string out-string ...
bindkey [ options ] in-string command ...
bindkey [ options ] [ in-string ]
  bindkey’s options can be divided into three categories: keymap selection for the current command, operation selection, and others. The keymap selection options are:

-e Selects keymap ‘emacs’ for any operations by the current command, and also links ‘emacs’ to ‘main’ so that it is selected by default the next time the editor starts.
-v Selects keymap ‘viins’ for any operations by the current command, and also links ‘viins’ to ‘main’ so that it is selected by default the next time the editor starts.
-a Selects keymap ‘vicmd’ for any operations by the current command.
-M keymap
  The keymap specifies a keymap name that is selected for any operations by the current command.
If a keymap selection is required and none of the options above are used, the ‘main’ keymap is used. Some operations do not permit a keymap to be selected, namely:
-l List all existing keymap names; if any arguments are given, list just those keymaps.

If the -L option is also used, list in the form of bindkey commands to create or link the keymaps. ‘bindkey -lL main’ shows which keymap is linked to ‘main’, if any, and hence if the standard emacs or vi emulation is in effect. This option does not show the .safe keymap because it cannot be created in that fashion; however, neither is ‘bindkey -lL .safe’ reported as an error, it simply outputs nothing.

-d Delete all existing keymaps and reset to the default state.
-D keymap ...
  Delete the named keymaps.
-A old-keymap new-keymap
  Make the new-keymap name an alias for old-keymap, so that both names refer to the same keymap. The names have equal standing; if either is deleted, the other remains. If there is already a keymap with the new-keymap name, it is deleted.
-N new-keymap [ old-keymap ]
  Create a new keymap, named new-keymap. If a keymap already has that name, it is deleted. If an old-keymap name is given, the new keymap is initialized to be a duplicate of it, otherwise the new keymap will be empty.
To use a newly created keymap, it should be linked to main. Hence the sequence of commands to create and use a new keymap ‘mymap’ initialized from the emacs keymap (which remains unchanged) is:

 
bindkey -N mymap emacs
bindkey -A mymap main

Note that while ‘bindkey -A newmap main’ will work when newmap is emacs or viins, it will not work for vicmd, as switching from vi insert to command mode becomes impossible.
The following operations act on the ‘main’ keymap if no keymap selection option was given:
-m Add the built-in set of meta-key bindings to the selected keymap. Only keys that are unbound or bound to self-insert are affected.
-r in-string ...
  Unbind the specified in-strings in the selected keymap. This is exactly equivalent to binding the strings to undefined-key.

When -R is also used, interpret the in-strings as ranges.

When -p is also used, the in-strings specify prefixes. Any binding that has the given in-string as a prefix, not including the binding for the in-string itself, if any, will be removed. For example,

 
bindkey -rpM viins ’^[’

will remove all bindings in the vi-insert keymap beginning with an escape character (probably cursor keys), but leave the binding for the escape character itself (probably vi-cmd-mode). This is incompatible with the option -R.

-s in-string out-string ...
  Bind each in-string to each out-string. When in-string is typed, out-string will be pushed back and treated as input to the line editor. When -R is also used, interpret the in-strings as ranges.

Note that both in-string and out-string are subject to the same form of interpretation, as described below.

in-string command ...
  Bind each in-string to each command. When -R is used, interpret the in-strings as ranges.
[ in-string ]
  List key bindings. If an in-string is specified, the binding of that string in the selected keymap is displayed. Otherwise, all key bindings in the selected keymap are displayed. (As a special case, if the -e or -v option is used alone, the keymap is not displayed - the implicit linking of keymaps is the only thing that happens.)

When the option -p is used, the in-string must be present. The listing shows all bindings which have the given key sequence as a prefix, not including any bindings for the key sequence itself.

When the -L option is used, the list is in the form of bindkey commands to create the key bindings.

When the -R option is used as noted above, a valid range consists of two characters, with an optional ‘-’ between them. All characters between the two specified, inclusive, are bound as specified.
For either in-string or out-string, the following escape sequences are recognised:
\a bell character
\b backspace
\e, \E escape
\f form feed
\n linefeed (newline)
\r carriage return
\t horizontal tab
\v vertical tab
\NNN character code in octal
\xNN character code in hexadecimal
\uNNNN unicode character code in hexadecimal
\UNNNNNNNN
  unicode character code in hexadecimal
\M[-]X character with meta bit set
\C[-]X control character
^X control character
In all other cases, ‘\’ escapes the following character. Delete is written as ‘^?’. Note that ‘\M^?’ and ‘^\M?’ are not the same, and that (unlike emacs), the bindings ‘\M-X’ and ‘\eX’ are entirely distinct, although they are initialized to the same bindings by ‘bindkey -m’.

vared [ -Aache ] [ -p prompt ] [ -r rprompt ]
[ -M main-keymap ] [ -m vicmd-keymap ]
[ -i init-widget ] [ -f finish-widget ]
[ -t tty ] name
  The value of the parameter name is loaded into the edit buffer, and the line editor is invoked. When the editor exits, name is set to the string value returned by the editor. When the -c flag is given, the parameter is created if it doesn’t already exist. The -a flag may be given with -c to create an array parameter, or the -A flag to create an associative array. If the type of an existing parameter does not match the type to be created, the parameter is unset and recreated.

If an array or array slice is being edited, separator characters as defined in $IFS will be shown quoted with a backslash, as will backslashes themselves. Conversely, when the edited text is split into an array, a backslash quotes an immediately following separator character or backslash; no other special handling of backslashes, or any handling of quotes, is performed.

Individual elements of existing array or associative array parameters may be edited by using subscript syntax on name. New elements are created automatically, even without -c.

If the -p flag is given, the following string will be taken as the prompt to display at the left. If the -r flag is given, the following string gives the prompt to display at the right. If the -h flag is specified, the history can be accessed from ZLE. If the -e flag is given, typing ^D (Control-D) on an empty line causes vared to exit immediately with a non-zero return value.

The -M option gives a keymap to link to the main keymap during editing, and the -m option gives a keymap to link to the vicmd keymap during editing. For vi-style editing, this allows a pair of keymaps to override viins and vicmd. For emacs-style editing, only -M is normally needed but the -m option may still be used. On exit, the previous keymaps will be restored.

Vared calls the usual ‘zle-line-init’ and ‘zle-line-finish’ hooks before and after it takes control. Using the -i and -f options, it is possible to replace these with other custom widgets.

If ‘-t tty’ is given, tty is the name of a terminal device to be used instead of the default /dev/tty. If tty does not refer to a terminal an error is reported.

zle
zle -l [ -L | -a ] [ string ... ]
zle -D widget ...
zle -A old-widget new-widget
zle -N widget [ function ]
zle -f flag [ flag... ]
zle -C widget completion-widget function
zle -R [ -c ] [ display-string ] [ string ... ]
zle -M string
zle -U string
zle -K keymap
zle -F [ -L | -w ] [ fd [ handler ] ]
zle -I
zle -T [ tc function | -r tc | -L ]
zle widget [ -n num ] [ -Nw ] [ -K keymap ] args ...
The zle builtin performs a number of different actions concerning ZLE.

With no options and no arguments, only the return status will be set. It is zero if ZLE is currently active and widgets could be invoked using this builtin command and non-zero otherwise. Note that even if non-zero status is returned, zle may still be active as part of the completion system; this does not allow direct calls to ZLE widgets.

Otherwise, which operation it performs depends on its options:

-l [ -L | -a ] [ string ]
  List all existing user-defined widgets. If the -L option is used, list in the form of zle commands to create the widgets.

When combined with the -a option, all widget names are listed, including the builtin ones. In this case the -L option is ignored.

If at least one string is given, and -a is present or -L is not used, nothing will be printed. The return status will be zero if all strings are names of existing widgets and non-zero if at least one string is not a name of a defined widget. If -a is also present, all widget names are used for the comparison including builtin widgets, else only user-defined widgets are used.

If at least one string is present and the -L option is used, user-defined widgets matching any string are listed in the form of zle commands to create the widgets.

-D widget ...
  Delete the named widgets.
-A old-widget new-widget
  Make the new-widget name an alias for old-widget, so that both names refer to the same widget. The names have equal standing; if either is deleted, the other remains. If there is already a widget with the new-widget name, it is deleted.
-N widget [ function ]
  Create a user-defined widget. If there is already a widget with the specified name, it is overwritten. When the new widget is invoked from within the editor, the specified shell function is called. If no function name is specified, it defaults to the same name as the widget. For further information, see the section ‘Widgets’ below.
-f flag [ flag... ]
  Set various flags on the running widget. Possible values for flag are:

yank for indicating that the widget has yanked text into the buffer. If the widget is wrapping an existing internal widget, no further action is necessary, but if it has inserted the text manually, then it should also take care to set YANK_START and YANK_END correctly. yankbefore does the same but is used when the yanked text appears after the cursor.

kill for indicating that text has been killed into the cutbuffer. When repeatedly invoking a kill widget, text is appended to the cutbuffer instead of replacing it, but when wrapping such widgets, it is necessary to call ‘zle -f kill’ to retain this effect.

-C widget completion-widget function
  Create a user-defined completion widget named widget. The completion widget will behave like the built-in completion-widget whose name is given as completion-widget. To generate the completions, the shell function function will be called. For further information, see zshcompwid(1).
-R [ -c ] [ display-string ] [ string ... ]
  Redisplay the command line; this is to be called from within a user-defined widget to allow changes to become visible. If a display-string is given and not empty, this is shown in the status line (immediately below the line being edited).

If the optional strings are given they are listed below the prompt in the same way as completion lists are printed. If no strings are given but the -c option is used such a list is cleared.

Note that this option is only useful for widgets that do not exit immediately after using it because the strings displayed will be erased immediately after return from the widget.

This command can safely be called outside user defined widgets; if zle is active, the display will be refreshed, while if zle is not active, the command has no effect. In this case there will usually be no other arguments.

The status is zero if zle was active, else one.

-M string
  As with the -R option, the string will be displayed below the command line; unlike the -R option, the string will not be put into the status line but will instead be printed normally below the prompt. This means that the string will still be displayed after the widget returns (until it is overwritten by subsequent commands).
-U string
  This pushes the characters in the string onto the input stack of ZLE. After the widget currently executed finishes ZLE will behave as if the characters in the string were typed by the user.

As ZLE uses a stack, if this option is used repeatedly the last string pushed onto the stack will be processed first. However, the characters in each string will be processed in the order in which they appear in the string.

-K keymap
  Selects the keymap named keymap. An error message will be displayed if there is no such keymap.

This keymap selection affects the interpretation of following keystrokes within this invocation of ZLE. Any following invocation (e.g., the next command line) will start as usual with the ‘main’ keymap selected.

-F [ -L | -w ] [ fd [ handler ] ]
  Only available if your system supports one of the ‘poll’ or ‘select’ system calls; most modern systems do.

Installs handler (the name of a shell function) to handle input from file descriptor fd. Installing a handler for an fd which is already handled causes the existing handler to be replaced. Any number of handlers for any number of readable file descriptors may be installed. Note that zle makes no attempt to check whether this fd is actually readable when installing the handler. The user must make their own arrangements for handling the file descriptor when zle is not active.

When zle is attempting to read data, it will examine both the terminal and the list of handled fd’s. If data becomes available on a handled fd, zle calls handler with the fd which is ready for reading as the first argument. Under normal circumstances this is the only argument, but if an error was detected, a second argument provides details: ‘hup’ for a disconnect, ‘nval’ for a closed or otherwise invalid descriptor, or ‘err’ for any other condition. Systems that support only the ‘select’ system call always use ‘err’.

If the option -w is also given, the handler is instead a line editor widget, typically a shell function made into a widget using ‘zle -N’. In that case handler can use all the facilities of zle to update the current editing line. Note, however, that as handling fd takes place at a low level changes to the display will not automatically appear; the widget should call ‘zle -R’ to force redisplay. As of this writing, widget handlers only support a single argument and thus are never passed a string for error state, so widgets must be prepared to test the descriptor themselves.

If either type of handler produces output to the terminal, it should call ‘zle -I’ before doing so (see below). Handlers should not attempt to read from the terminal.

If no handler is given, but an fd is present, any handler for that fd is removed. If there is none, an error message is printed and status 1 is returned.

If no arguments are given, or the -L option is supplied, a list of handlers is printed in a form which can be stored for later execution.

An fd (but not a handler) may optionally be given with the -L option; in this case, the function will list the handler if any, else silently return status 1.

Note that this feature should be used with care. Activity on one of the fd’s which is not properly handled can cause the terminal to become unusable. Removing an fd handler from within a signal trap may cause unpredictable behavior.

Here is a simple example of using this feature. A connection to a remote TCP port is created using the ztcp command; see the description of the zsh/net/tcp module in zshmodules(1). Then a handler is installed which simply prints out any data which arrives on this connection. Note that ‘select’ will indicate that the file descriptor needs handling if the remote side has closed the connection; we handle that by testing for a failed read.

 
if ztcp pwspc 2811; then
  tcpfd=$REPLY
  handler() {
    zle -I
    local line
    if ! read -r line <&$1; then
      # select marks this fd if we reach EOF,
      # so handle this specially.
      print "[Read on fd $1 failed, removing.]" >&2
      zle -F $1
      return 1
    fi
    print -r - $line
  }
  zle -F $tcpfd handler
fi

-I Unusually, this option is most useful outside ordinary widget functions, though it may be used within if normal output to the terminal is required. It invalidates the current zle display in preparation for output; typically this will be from a trap function. It has no effect if zle is not active. When a trap exits, the shell checks to see if the display needs restoring, hence the following will print output in such a way as not to disturb the line being edited:

 
TRAPUSR1() {
  # Invalidate zle display
  [[ -o zle ]] && zle -I
  # Show output
  print Hello
}

In general, the trap function may need to test whether zle is active before using this method (as shown in the example), since the zsh/zle module may not even be loaded; if it is not, the command can be skipped.

It is possible to call ‘zle -I’ several times before control is returned to the editor; the display will only be invalidated the first time to minimise disruption.

Note that there are normally better ways of manipulating the display from within zle widgets; see, for example, ‘zle -R’ above.

The returned status is zero if zle was invalidated, even though this may have been by a previous call to ‘zle -I’ or by a system notification. To test if a zle widget may be called at this point, execute zle with no arguments and examine the return status.

-T This is used to add, list or remove internal transformations on the processing performed by the line editor. It is typically used only for debugging or testing and is therefore of little interest to the general user.

zle -T transformation func’ specifies that the given transformation (see below) is effected by shell function func.

zle -Tr transformation’ removes the given transformation if it was present (it is not an error if none was).

zle -TL’ can be used to list all transformations currently in operation.

Currently the only transformation is tc. This is used instead of outputting termcap codes to the terminal. When the transformation is in operation the shell function is passed the termcap code that would be output as its first argument; if the operation required a numeric argument, that is passed as a second argument. The function should set the shell variable REPLY to the transformed termcap code. Typically this is used to produce some simply formatted version of the code and optional argument for debugging or testing. Note that this transformation is not applied to other non-printing characters such as carriage returns and newlines.

widget [ -n num ] [ -Nw ] [ -K keymap ] args ...
  Invoke the specified widget. This can only be done when ZLE is active; normally this will be within a user-defined widget.

With the options -n and -N, the current numeric argument will be saved and then restored after the call to widget; ‘-n num’ sets the numeric argument temporarily to num, while ‘-N’ sets it to the default, i.e. as if there were none.

With the option -K, keymap will be used as the current keymap during the execution of the widget. The previous keymap will be restored when the widget exits.

Normally, calling a widget in this way does not set the special parameter WIDGET and related parameters, so that the environment appears as if the top-level widget called by the user were still active. With the option -w, WIDGET and related parameters are set to reflect the widget being executed by the zle call.

Any further arguments will be passed to the widget; note that as standard argument handling is performed, any general argument list should be preceded by --. If it is a shell function, these are passed down as positional parameters; for builtin widgets it is up to the widget in question what it does with them. Currently arguments are only handled by the incremental-search commands, the history-search-forward and -backward and the corresponding functions prefixed by vi-, and by universal-argument. No error is flagged if the command does not use the arguments, or only uses some of them.

The return status reflects the success or failure of the operation carried out by the widget, or if it is a user-defined widget the return status of the shell function.

A non-zero return status causes the shell to beep when the widget exits, unless the BEEP options was unset or the widget was called via the zle command. Thus if a user defined widget requires an immediate beep, it should call the beep widget directly.

WIDGETS

All actions in the editor are performed by ‘widgets’. A widget’s job is simply to perform some small action. The ZLE commands that key sequences in keymaps are bound to are in fact widgets. Widgets can be user-defined or built in.

The standard widgets built into ZLE are listed in Standard Widgets below. Other built-in widgets can be defined by other modules (see zshmodules(1)). Each built-in widget has two names: its normal canonical name, and the same name preceded by a ‘.’. The ‘.’ name is special: it can’t be rebound to a different widget. This makes the widget available even when its usual name has been redefined.

User-defined widgets are defined using ‘zle -N’, and implemented as shell functions. When the widget is executed, the corresponding shell function is executed, and can perform editing (or other) actions. It is recommended that user-defined widgets should not have names starting with ‘.’.

USER-DEFINED WIDGETS

User-defined widgets, being implemented as shell functions, can execute any normal shell command. They can also run other widgets (whether built-in or user-defined) using the zle builtin command. The standard input of the function is closed to prevent external commands from unintentionally blocking ZLE by reading from the terminal, but read -k or read -q can be used to read characters. Finally, they can examine and edit the ZLE buffer being edited by reading and setting the special parameters described below.

These special parameters are always available in widget functions, but are not in any way special outside ZLE. If they have some normal value outside ZLE, that value is temporarily inaccessible, but will return when the widget function exits. These special parameters in fact have local scope, like parameters created in a function using local.

Inside completion widgets and traps called while ZLE is active, these parameters are available read-only.

Note that the parameters appear as local to any ZLE widget in which they appear. Hence if it is desired to override them this needs to be done within a nested function:

widget-function() {
  # $WIDGET here refers to the special variable
  # that is local inside widget-function
  () {
     # This anonymous nested function allows WIDGET
     # to be used as a local variable.  The -h
     # removes the special status of the variable.
     local -h WIDGET
  }
}

BUFFER (scalar)
  The entire contents of the edit buffer. If it is written to, the cursor remains at the same offset, unless that would put it outside the buffer.
BUFFERLINES (integer)
  The number of screen lines needed for the edit buffer currently displayed on screen (i.e. without any changes to the preceding parameters done after the last redisplay); read-only.
CONTEXT (scalar)
  The context in which zle was called to read a line; read-only. One of the values:

start The start of a command line (at prompt PS1).
cont A continuation to a command line (at prompt PS2).
select In a select loop.
vared Editing a variable in vared.

CURSOR (integer)
  The offset of the cursor, within the edit buffer. This is in the range 0 to $#BUFFER, and is by definition equal to $#LBUFFER. Attempts to move the cursor outside the buffer will result in the cursor being moved to the appropriate end of the buffer.
CUTBUFFER (scalar)
  The last item cut using one of the ‘kill-’ commands; the string which the next yank would insert in the line. Later entries in the kill ring are in the array killring. Note that the command ‘zle copy-region-as-kill string’ can be used to set the text of the cut buffer from a shell function and cycle the kill ring in the same way as interactively killing text.
HISTNO (integer)
  The current history number. Setting this has the same effect as moving up or down in the history to the corresponding history line. An attempt to set it is ignored if the line is not stored in the history. Note this is not the same as the parameter HISTCMD, which always gives the number of the history line being added to the main shell’s history. HISTNO refers to the line being retrieved within zle.
KEYMAP (scalar)
  The name of the currently selected keymap; read-only.
KEYS (scalar)
  The keys typed to invoke this widget, as a literal string; read-only.
killring (array)
  The array of previously killed items, with the most recently killed first. This gives the items that would be retrieved by a yank-pop in the same order. Note, however, that the most recently killed item is in $CUTBUFFER; $killring shows the array of previous entries.

The default size for the kill ring is eight, however the length may be changed by normal array operations. Any empty string in the kill ring is ignored by the yank-pop command, hence the size of the array effectively sets the maximum length of the kill ring, while the number of non-zero strings gives the current length, both as seen by the user at the command line.

LASTABORTEDSEARCH (scalar)
  The last search string used by an interactive search that was aborted by the user (status 3 returned by the search widget).
LASTSEARCH (scalar)
  The last search string used by an interactive search; read-only. This is set even if the search failed (status 0, 1 or 2 returned by the search widget), but not if it was aborted by the user.
LASTWIDGET (scalar)
  The name of the last widget that was executed; read-only.
LBUFFER (scalar)
  The part of the buffer that lies to the left of the cursor position. If it is assigned to, only that part of the buffer is replaced, and the cursor remains between the new $LBUFFER and the old $RBUFFER.
MARK (integer)
  Like CURSOR, but for the mark. With vi-mode operators that wait for a movement command to select a region of text, setting MARK allows the selection to extend in both directions from the the initial cursor position.
NUMERIC (integer)
  The numeric argument. If no numeric argument was given, this parameter is unset. When this is set inside a widget function, builtin widgets called with the zle builtin command will use the value assigned. If it is unset inside a widget function, builtin widgets called behave as if no numeric argument was given.
PENDING (integer)
  The number of bytes pending for input, i.e. the number of bytes which have already been typed and can immediately be read. On systems where the shell is not able to get this information, this parameter will always have a value of zero. Read-only.
PREBUFFER (scalar)
  In a multi-line input at the secondary prompt, this read-only parameter contains the contents of the lines before the one the cursor is currently in.
PREDISPLAY (scalar)
  Text to be displayed before the start of the editable text buffer. This does not have to be a complete line; to display a complete line, a newline must be appended explicitly. The text is reset on each new invocation (but not recursive invocation) of zle.
POSTDISPLAY (scalar)
  Text to be displayed after the end of the editable text buffer. This does not have to be a complete line; to display a complete line, a newline must be prepended explicitly. The text is reset on each new invocation (but not recursive invocation) of zle.
RBUFFER (scalar)
  The part of the buffer that lies to the right of the cursor position. If it is assigned to, only that part of the buffer is replaced, and the cursor remains between the old $LBUFFER and the new $RBUFFER.
REGION_ACTIVE (integer)
  Indicates if the region is currently active. It can be assigned 0 or 1 to deactivate and activate the region respectively. A value of 2 activates the region in line-wise mode with the highlighted text extending for whole lines only; see Character Highlighting below.
region_highlight (array)
  Each element of this array may be set to a string that describes highlighting for an arbitrary region of the command line that will take effect the next time the command line is redisplayed. Highlighting of the non-editable parts of the command line in PREDISPLAY and POSTDISPLAY are possible, but note that the P flag is needed for character indexing to include PREDISPLAY.

Each string consists of the following parts:

o Optionally, a ‘P’ to signify that the start and end offset that follow include any string set by the PREDISPLAY special parameter; this is needed if the predisplay string itself is to be highlighted. Whitespace may follow the ‘P’.
o A start offset in the same units as CURSOR, terminated by whitespace.
o An end offset in the same units as CURSOR, terminated by whitespace.
o A highlight specification in the same format as used for contexts in the parameter zle_highlight, see the section ‘Character Highlighting’ below; for example, standout or fg=red,bold
For example,

 
region_highlight=("P0 20 bold")

specifies that the first twenty characters of the text including any predisplay string should be highlighted in bold.

Note that the effect of region_highlight is not saved and disappears as soon as the line is accepted.

The final highlighting on the command line depends on both region_highlight and zle_highlight; see the section CHARACTER HIGHLIGHTING below for details.

UNDO_CHANGE_NO (integer)
  A number representing the state of the undo history. The only use of this is passing as an argument to the undo widget in order to undo back to the recorded point. Read-only.
UNDO_LIMIT_NO (integer)
  A number corresponding to an existing change in the undo history; compare UNDO_CHANGE_NO. If this is set to a value greater than zero, the undo command will not allow the line to be undone beyond the given change number. It is still possible to use ‘zle undo change’ in a widget to undo beyond that point; in that case, it will not be possible to undo at all until UNDO_LIMIT_NO is reduced. Set to 0 to disable the limit.

A typical use of this variable in a widget function is as follows (note the additional function scope is required):

 
() {
  local UNDO_LIMIT_NO=$UNDO_CHANGE_NO
  # Perform some form of recursive edit.
}

WIDGET (scalar)
  The name of the widget currently being executed; read-only.
WIDGETFUNC (scalar)
  The name of the shell function that implements a widget defined with either zle -N or zle -C. In the former case, this is the second argument to the zle -N command that defined the widget, or the first argument if there was no second argument. In the latter case this is the third argument to the zle -C command that defined the widget. Read-only.
WIDGETSTYLE (scalar)
  Describes the implementation behind the completion widget currently being executed; the second argument that followed zle -C when the widget was defined. This is the name of a builtin completion widget. For widgets defined with zle -N this is set to the empty string. Read-only.
YANK_ACTIVE (integer)
YANK_START (integer)
YANK_END (integer)
  YANK_ACTIVE indicates whether text has just been yanked (pasted) into the buffer. YANK_START and YANK_END give the location of the pasted text and are in the same units as CURSOR. They are only valid for reading when YANK_ACTIVE is non-zero. They can also be assigned by widgets that insert text in a yank-like fashion, for example wrappers of bracketed-paste. See also zle -f.

YANK_ACTIVE is read-only.

ZLE_STATE (scalar)
  Contains a set of space-separated words that describe the current zle state.

Currently, the states shown are the insert mode as set by the overwrite-mode or vi-replace widgets and whether history commands will visit imported entries as controlled by the set-local-history widget. The string contains ‘insert’ if characters to be inserted on the command line move existing characters to the right or ‘overwrite’ if characters to be inserted overwrite existing characters. It contains ‘localhistory’ if only local history commands will be visited or ‘globalhistory’ if imported history commands will also be visited.

The substrings are sorted in alphabetical order so that if you want to test for two specific substrings in a future-proof way, you can do match by doing:

 
if [[ $ZLE_STATE == *globalhistory*insert* ]]; then ...; fi

    Special Widgets

There are a few user-defined widgets which are special to the shell. If they do not exist, no special action is taken. The environment provided is identical to that for any other editing widget.

zle-isearch-exit
  Executed at the end of incremental search at the point where the isearch prompt is removed from the display. See zle-isearch-update for an example.
zle-isearch-update
  Executed within incremental search when the display is about to be redrawn. Additional output below the incremental search prompt can be generated by using ‘zle -M’ within the widget. For example,

 
zle-isearch-update() { zle -M "Line $HISTNO"; }
zle -N zle-isearch-update

Note the line output by ‘zle -M’ is not deleted on exit from incremental search. This can be done from a zle-isearch-exit widget:

 
zle-isearch-exit() { zle -M ""; }
zle -N zle-isearch-exit

zle-line-init
  Executed every time the line editor is started to read a new line of input. The following example puts the line editor into vi command mode when it starts up.

 
zle-line-init() { zle -K vicmd; }
zle -N zle-line-init

(The command inside the function sets the keymap directly; it is equivalent to zle vi-cmd-mode.)

zle-line-finish
  This is similar to zle-line-init but is executed every time the line editor has finished reading a line of input.
zle-history-line-set
  Executed when the history line changes.
zle-keymap-select
  Executed every time the keymap changes, i.e. the special parameter KEYMAP is set to a different value, while the line editor is active. Initialising the keymap when the line editor starts does not cause the widget to be called.

The value $KEYMAP within the function reflects the new keymap. The old keymap is passed as the sole argument.

This can be used for detecting switches between the vi command (vicmd) and insert (usually main) keymaps.

STANDARD WIDGETS

The following is a list of all the standard widgets, and their default bindings in emacs mode, vi command mode and vi insert mode (the ‘emacs’, ‘vicmd’ and ‘viins’ keymaps, respectively).

Note that cursor keys are bound to movement keys in all three keymaps; the shell assumes that the cursor keys send the key sequences reported by the terminal-handling library (termcap or terminfo). The key sequences shown in the list are those based on the VT100, common on many modern terminals, but in fact these are not necessarily bound. In the case of the viins keymap, the initial escape character of the sequences serves also to return to the vicmd keymap: whether this happens is determined by the KEYTIMEOUT parameter, see zshparam(1).

    Movement

vi-backward-blank-word (unbound) (B) (unbound)
  Move backward one word, where a word is defined as a series of non-blank characters.
vi-backward-blank-word-end (unbound) (gE) (unbound)
  Move to the end of the previous word, where a word is defined as a series of non-blank characters.
backward-char (^B ESC-[D) (unbound) (unbound)
  Move backward one character.
vi-backward-char (unbound) (^H h ^?) (ESC-[D)
  Move backward one character, without changing lines.
backward-word (ESC-B ESC-b) (unbound) (unbound)
  Move to the beginning of the previous word.
emacs-backward-word
  Move to the beginning of the previous word.
vi-backward-word (unbound) (b) (unbound)
  Move to the beginning of the previous word, vi-style.
vi-backward-word-end (unbound) (ge) (unbound)
  Move to the end of the previous word, vi-style.
beginning-of-line (^A) (unbound) (unbound)
  Move to the beginning of the line. If already at the beginning of the line, move to the beginning of the previous line, if any.
vi-beginning-of-line
  Move to the beginning of the line, without changing lines.
down-line (unbound) (unbound) (unbound)
  Move down a line in the buffer.
end-of-line (^E) (unbound) (unbound)
  Move to the end of the line. If already at the end of the line, move to the end of the next line, if any.
vi-end-of-line (unbound) ($) (unbound)
  Move to the end of the line. If an argument is given to this command, the cursor will be moved to the end of the line (argument - 1) lines down.
vi-forward-blank-word (unbound) (W) (unbound)
  Move forward one word, where a word is defined as a series of non-blank characters.
vi-forward-blank-word-end (unbound) (E) (unbound)
  Move to the end of the current word, or, if at the end of the current word, to the end of the next word, where a word is defined as a series of non-blank characters.
forward-char (^F ESC-[C) (unbound) (unbound)
  Move forward one character.
vi-forward-char (unbound) (space l) (ESC-[C)
  Move forward one character.
vi-find-next-char (^X^F) (f) (unbound)
  Read a character from the keyboard, and move to the next occurrence of it in the line.
vi-find-next-char-skip (unbound) (t) (unbound)
  Read a character from the keyboard, and move to the position just before the next occurrence of it in the line.
vi-find-prev-char (unbound) (F) (unbound)
  Read a character from the keyboard, and move to the previous occurrence of it in the line.
vi-find-prev-char-skip (unbound) (T) (unbound)
  Read a character from the keyboard, and move to the position just after the previous occurrence of it in the line.
vi-first-non-blank (unbound) (^) (unbound)
  Move to the first non-blank character in the line.
vi-forward-word (unbound) (w) (unbound)
  Move forward one word, vi-style.
forward-word (ESC-F ESC-f) (unbound) (unbound)
  Move to the beginning of the next word. The editor’s idea of a word is specified with the WORDCHARS parameter.
emacs-forward-word
  Move to the end of the next word.
vi-forward-word-end (unbound) (e) (unbound)
  Move to the end of the next word.
vi-goto-column (ESC-|) (|) (unbound)
  Move to the column specified by the numeric argument.
vi-goto-mark (unbound) () (unbound)
  Move to the specified mark.
vi-goto-mark-line (unbound) () (unbound)
  Move to beginning of the line containing the specified mark.
vi-repeat-find (unbound) (;) (unbound)
  Repeat the last vi-find command.
vi-rev-repeat-find (unbound) (,) (unbound)
  Repeat the last vi-find command in the opposite direction.
up-line (unbound) (unbound) (unbound)
  Move up a line in the buffer.

    History Control

beginning-of-buffer-or-history (ESC-<) (gg) (unbound)
  Move to the beginning of the buffer, or if already there, move to the first event in the history list.
beginning-of-line-hist
  Move to the beginning of the line. If already at the beginning of the buffer, move to the previous history line.
beginning-of-history
  Move to the first event in the history list.
down-line-or-history (^N ESC-[B) (j) (ESC-[B)
  Move down a line in the buffer, or if already at the bottom line, move to the next event in the history list.
vi-down-line-or-history (unbound) (+) (unbound)
  Move down a line in the buffer, or if already at the bottom line, move to the next event in the history list. Then move to the first non-blank character on the line.
down-line-or-search
  Move down a line in the buffer, or if already at the bottom line, search forward in the history for a line beginning with the first word in the buffer.

If called from a function by the zle command with arguments, the first argument is taken as the string for which to search, rather than the first word in the buffer.

down-history (unbound) (^N) (unbound)
  Move to the next event in the history list.
history-beginning-search-backward
  Search backward in the history for a line beginning with the current line up to the cursor. This leaves the cursor in its original position.
end-of-buffer-or-history (ESC->) (unbound) (unbound)
  Move to the end of the buffer, or if already there, move to the last event in the history list.
end-of-line-hist
  Move to the end of the line. If already at the end of the buffer, move to the next history line.
end-of-history
  Move to the last event in the history list.
vi-fetch-history (unbound) (G) (unbound)
  Fetch the history line specified by the numeric argument. This defaults to the current history line (i.e. the one that isn’t history yet).
history-incremental-search-backward (^R ^Xr) (unbound) (unbound)
  Search backward incrementally for a specified string. The search is case-insensitive if the search string does not have uppercase letters and no numeric argument was given. The string may begin with ‘^’ to anchor the search to the beginning of the line. When called from a user-defined function returns the following statuses: 0, if the search succeeded; 1, if the search failed; 2, if the search term was a bad pattern; 3, if the search was aborted by the send-break command.

A restricted set of editing functions is available in the mini-buffer. Keys are looked up in the special isearch keymap, and if not found there in the main keymap (note that by default the isearch keymap is empty). An interrupt signal, as defined by the stty setting, will stop the search and go back to the original line. An undefined key will have the same effect. Note that the following always perform the same task within incremental searches and cannot be replaced by user defined widgets, nor can the set of functions be extended. The supported functions are:

accept-and-hold
accept-and-infer-next-history
accept-line
accept-line-and-down-history
  Perform the usual function after exiting incremental search. The command line displayed is executed.
backward-delete-char
vi-backward-delete-char
  Back up one place in the search history. If the search has been repeated this does not immediately erase a character in the minibuffer.
accept-search
  Exit incremental search, retaining the command line but performing no further action. Note that this function is not bound by default and has no effect outside incremental search.
backward-delete-word
backward-kill-word
vi-backward-kill-word
  Back up one character in the minibuffer; if multiple searches have been performed since the character was inserted the search history is rewound to the point just before the character was entered. Hence this has the effect of repeating backward-delete-char.
clear-screen
  Clear the screen, remaining in incremental search mode.
history-incremental-search-backward
  Find the next occurrence of the contents of the mini-buffer. If the mini-buffer is empty, the most recent previously used search string is reinstated.
history-incremental-search-forward
  Invert the sense of the search.
magic-space
  Inserts a non-magical space.
quoted-insert
vi-quoted-insert
  Quote the character to insert into the minibuffer.
redisplay
  Redisplay the command line, remaining in incremental search mode.
vi-cmd-mode
  Select the ‘vicmd’ keymap; the ‘main’ keymap (insert mode) will be selected initially.

In addition, the modifications that were made while in vi insert mode are merged to form a single undo event.

vi-repeat-search
vi-rev-repeat-search
  Repeat the search. The direction of the search is indicated in the mini-buffer.
Any character that is not bound to one of the above functions, or self-insert or self-insert-unmeta, will cause the mode to be exited. The character is then looked up and executed in the keymap in effect at that point.
When called from a widget function by the zle command, the incremental search commands can take a string argument. This will be treated as a string of keys, as for arguments to the bindkey command, and used as initial input for the command. Any characters in the string which are unused by the incremental search will be silently ignored. For example,

 
zle history-incremental-search-backward forceps

will search backwards for forceps, leaving the minibuffer containing the string ‘forceps’.

history-incremental-search-forward (^S ^Xs) (unbound) (unbound)
  Search forward incrementally for a specified string. The search is case-insensitive if the search string does not have uppercase letters and no numeric argument was given. The string may begin with ‘^’ to anchor the search to the beginning of the line. The functions available in the mini-buffer are the same as for history-incremental-search-backward.
history-incremental-pattern-search-backward
history-incremental-pattern-search-forward
  These widgets behave similarly to the corresponding widgets with no -pattern, but the search string typed by the user is treated as a pattern, respecting the current settings of the various options affecting pattern matching. See FILENAME GENERATION in zshexpn(1) for a description of patterns. If no numeric argument was given lowercase letters in the search string may match uppercase letters in the history. The string may begin with ‘^’ to anchor the search to the beginning of the line.

The prompt changes to indicate an invalid pattern; this may simply indicate the pattern is not yet complete.

Note that only non-overlapping matches are reported, so an expression with wildcards may return fewer matches on a line than are visible by inspection.

history-search-backward (ESC-P ESC-p) (unbound) (unbound)
  Search backward in the history for a line beginning with the first word in the buffer.

If called from a function by the zle command with arguments, the first argument is taken as the string for which to search, rather than the first word in the buffer.

vi-history-search-backward (unbound) (/) (unbound)
  Search backward in the history for a specified string. The string may begin with ‘^’ to anchor the search to the beginning of the line.

A restricted set of editing functions is available in the mini-buffer. An interrupt signal, as defined by the stty setting, will stop the search. The functions available in the mini-buffer are: accept-line, backward-delete-char, vi-backward-delete-char, backward-kill-word, vi-backward-kill-word, clear-screen, redisplay, quoted-insert and vi-quoted-insert.

vi-cmd-mode is treated the same as accept-line, and magic-space is treated as a space. Any other character that is not bound to self-insert or self-insert-unmeta will beep and be ignored. If the function is called from vi command mode, the bindings of the current insert mode will be used.

If called from a function by the zle command with arguments, the first argument is taken as the string for which to search, rather than the first word in the buffer.

history-search-forward (ESC-N ESC-n) (unbound) (unbound)
  Search forward in the history for a line beginning with the first word in the buffer.

If called from a function by the zle command with arguments, the first argument is taken as the string for which to search, rather than the first word in the buffer.

vi-history-search-forward (unbound) (?) (unbound)
  Search forward in the history for a specified string. The string may begin with ‘^’ to anchor the search to the beginning of the line. The functions available in the mini-buffer are the same as for vi-history-search-backward. Argument handling is also the same as for that command.
infer-next-history (^X^N) (unbound) (unbound)
  Search in the history list for a line matching the current one and fetch the event following it.
insert-last-word (ESC-_ ESC-.) (unbound) (unbound)
  Insert the last word from the previous history event at the cursor position. If a positive numeric argument is given, insert that word from the end of the previous history event. If the argument is zero or negative insert that word from the left (zero inserts the previous command word). Repeating this command replaces the word just inserted with the last word from the history event prior to the one just used; numeric arguments can be used in the same way to pick a word from that event.

When called from a shell function invoked from a user-defined widget, the command can take one to three arguments. The first argument specifies a history offset which applies to successive calls to this widget: if it is -1, the default behaviour is used, while if it is 1, successive calls will move forwards through the history. The value 0 can be used to indicate that the history line examined by the previous execution of the command will be reexamined. Note that negative numbers should be preceded by a ‘--’ argument to avoid confusing them with options.

If two arguments are given, the second specifies the word on the command line in normal array index notation (as a more natural alternative to the numeric argument). Hence 1 is the first word, and -1 (the default) is the last word.

If a third argument is given, its value is ignored, but it is used to signify that the history offset is relative to the current history line, rather than the one remembered after the previous invocations of insert-last-word.

For example, the default behaviour of the command corresponds to

 
zle insert-last-word -- -1 -1

while the command

 
zle insert-last-word -- -1 1 -

always copies the first word of the line in the history immediately before the line being edited. This has the side effect that later invocations of the widget will be relative to that line.

vi-repeat-search (unbound) (n) (unbound)
  Repeat the last vi history search.
vi-rev-repeat-search (unbound) (N) (unbound)
  Repeat the last vi history search, but in reverse.
up-line-or-history (^P ESC-[A) (k) (ESC-[A)
  Move up a line in the buffer, or if already at the top line, move to the previous event in the history list.
vi-up-line-or-history (unbound) (-) (unbound)
  Move up a line in the buffer, or if already at the top line, move to the previous event in the history list. Then move to the first non-blank character on the line.
up-line-or-search
  Move up a line in the buffer, or if already at the top line, search backward in the history for a line beginning with the first word in the buffer.

If called from a function by the zle command with arguments, the first argument is taken as the string for which to search, rather than the first word in the buffer.

up-history (unbound) (^P) (unbound)
  Move to the previous event in the history list.
history-beginning-search-forward
  Search forward in the history for a line beginning with the current line up to the cursor. This leaves the cursor in its original position.
set-local-history
  By default, history movement commands visit the imported lines as well as the local lines. This widget lets you toggle this on and off, or set it with the numeric argument. Zero for both local and imported lines and nonzero for only local lines.

    Modifying Text

vi-add-eol (unbound) (A) (unbound)
  Move to the end of the line and enter insert mode.
vi-add-next (unbound) (a) (unbound)
  Enter insert mode after the current cursor position, without changing lines.
backward-delete-char (^H ^?) (unbound) (unbound)
  Delete the character behind the cursor.
vi-backward-delete-char (unbound) (X) (^H)
  Delete the character behind the cursor, without changing lines. If in insert mode, this won’t delete past the point where insert mode was last entered.
backward-delete-word
  Delete the word behind the cursor.
backward-kill-line
  Kill from the beginning of the line to the cursor position.
backward-kill-word (^W ESC-^H ESC-^?) (unbound) (unbound)
  Kill the word behind the cursor.
vi-backward-kill-word (unbound) (unbound) (^W)
  Kill the word behind the cursor, without going past the point where insert mode was last entered.
capitalize-word (ESC-C ESC-c) (unbound) (unbound)
  Capitalize the current word and move past it.
vi-change (unbound) (c) (unbound)
  Read a movement command from the keyboard, and kill from the cursor position to the endpoint of the movement. Then enter insert mode. If the command is vi-change, change the current line.

For compatibility with vi, if the command is vi-forward-word or vi-forward-blank-word, the whitespace after the word is not included. If you prefer the more consistent behaviour with the whitespace included use the following key binding:

 
bindkey -a -s cw dwi

vi-change-eol (unbound) (C) (unbound)
  Kill to the end of the line and enter insert mode.
vi-change-whole-line (unbound) (S) (unbound)
  Kill the current line and enter insert mode.
copy-region-as-kill (ESC-W ESC-w) (unbound) (unbound)
  Copy the area from the cursor to the mark to the kill buffer.

If called from a ZLE widget function in the form ‘zle copy-region-as-kill string’ then string will be taken as the text to copy to the kill buffer. The cursor, the mark and the text on the command line are not used in this case.

copy-prev-word (ESC-^_) (unbound) (unbound)
  Duplicate the word to the left of the cursor.
copy-prev-shell-word
  Like copy-prev-word, but the word is found by using shell parsing, whereas copy-prev-word looks for blanks. This makes a difference when the word is quoted and contains spaces.
vi-delete (unbound) (d) (unbound)
  Read a movement command from the keyboard, and kill from the cursor position to the endpoint of the movement. If the command is vi-delete, kill the current line.
delete-char
  Delete the character under the cursor.
vi-delete-char (unbound) (x) (unbound)
  Delete the character under the cursor, without going past the end of the line.
delete-word
  Delete the current word.
down-case-word (ESC-L ESC-l) (unbound) (unbound)
  Convert the current word to all lowercase and move past it.
kill-word (ESC-D ESC-d) (unbound) (unbound)
  Kill the current word.
gosmacs-transpose-chars
  Exchange the two characters behind the cursor.
vi-indent (unbound) (>) (unbound)
  Indent a number of lines.
vi-insert (unbound) (i) (unbound)
  Enter insert mode.
vi-insert-bol (unbound) (I) (unbound)
  Move to the first non-blank character on the line and enter insert mode.
vi-join (^X^J) (J) (unbound)
  Join the current line with the next one.
kill-line (^K) (unbound) (unbound)
  Kill from the cursor to the end of the line. If already on the end of the line, kill the newline character.
vi-kill-line (unbound) (unbound) (^U)
  Kill from the cursor back to wherever insert mode was last entered.
vi-kill-eol (unbound) (D) (unbound)
  Kill from the cursor to the end of the line.
kill-region
  Kill from the cursor to the mark.
kill-buffer (^X^K) (unbound) (unbound)
  Kill the entire buffer.
kill-whole-line (^U) (unbound) (unbound)
  Kill the current line.
vi-match-bracket (^X^B) (%) (unbound)
  Move to the bracket character (one of {}, () or []) that matches the one under the cursor. If the cursor is not on a bracket character, move forward without going past the end of the line to find one, and then go to the matching bracket.
vi-open-line-above (unbound) (O) (unbound)
  Open a line above the cursor and enter insert mode.
vi-open-line-below (unbound) (o) (unbound)
  Open a line below the cursor and enter insert mode.
vi-oper-swap-case (unbound) (g~) (unbound)
  Read a movement command from the keyboard, and swap the case of all characters from the cursor position to the endpoint of the movement. If the movement command is vi-oper-swap-case, swap the case of all characters on the current line.
overwrite-mode (^X^O) (unbound) (unbound)
  Toggle between overwrite mode and insert mode.
vi-put-before (unbound) (P) (unbound)
  Insert the contents of the kill buffer before the cursor. If the kill buffer contains a sequence of lines (as opposed to characters), paste it above the current line.
vi-put-after (unbound) (p) (unbound)
  Insert the contents of the kill buffer after the cursor. If the kill buffer contains a sequence of lines (as opposed to characters), paste it below the current line.
put-replace-selection (unbound) (unbound) (unbound)
  Replace the contents of the current region or selection with the contents of the kill buffer. If the kill buffer contains a sequence of lines (as opposed to characters), the current line will be split by the pasted lines.
quoted-insert (^V) (unbound) (unbound)
  Insert the next character typed into the buffer literally. An interrupt character will not be inserted.
vi-quoted-insert (unbound) (unbound) (^Q ^V)
  Display a ‘^’ at the cursor position, and insert the next character typed into the buffer literally. An interrupt character will not be inserted.
quote-line (ESC-’) (unbound) (unbound)
  Quote the current line; that is, put a ‘’ character at the beginning and the end, and convert all ‘’ characters to ‘’\’’’.
quote-region (ESC-") (unbound) (unbound)
  Quote the region from the cursor to the mark.
vi-replace (unbound) (R) (unbound)
  Enter overwrite mode.
vi-repeat-change (unbound) (.) (unbound)
  Repeat the last vi mode text modification. If a count was used with the modification, it is remembered. If a count is given to this command, it overrides the remembered count, and is remembered for future uses of this command. The cut buffer specification is similarly remembered.
vi-replace-chars (unbound) (r) (unbound)
  Replace the character under the cursor with a character read from the keyboard.
self-insert (printable characters) (unbound) (printable characters and some control characters)
  Insert a character into the buffer at the cursor position.
self-insert-unmeta (ESC-^I ESC-^J ESC-^M) (unbound) (unbound)
  Insert a character into the buffer after stripping the meta bit and converting ^M to ^J.
vi-substitute (unbound) (s) (unbound)
  Substitute the next character(s).
vi-swap-case (unbound) (~) (unbound)
  Swap the case of the character under the cursor and move past it.
transpose-chars (^T) (unbound) (unbound)
  Exchange the two characters to the left of the cursor if at end of line, else exchange the character under the cursor with the character to the left.
transpose-words (ESC-T ESC-t) (unbound) (unbound)
  Exchange the current word with the one before it.
vi-unindent (unbound) (<) (unbound)
  Unindent a number of lines.
up-case-word (ESC-U ESC-u) (unbound) (unbound)
  Convert the current word to all caps and move past it.
yank (^Y) (unbound) (unbound)
  Insert the contents of the kill buffer at the cursor position.
yank-pop (ESC-y) (unbound) (unbound)
  Remove the text just yanked, rotate the kill-ring (the history of previously killed text) and yank the new top. Only works following yank, vi-put-before, vi-put-after or yank-pop.
vi-yank (unbound) (y) (unbound)
  Read a movement command from the keyboard, and copy the region from the cursor position to the endpoint of the movement into the kill buffer. If the command is vi-yank, copy the current line.
vi-yank-whole-line (unbound) (Y) (unbound)
  Copy the current line into the kill buffer.
vi-yank-eol
  Copy the region from the cursor position to the end of the line into the kill buffer. Arguably, this is what Y should do in vi, but it isn’t what it actually does.

    Arguments

digit-argument (ESC-0..ESC-9) (1-9) (unbound)
  Start a new numeric argument, or add to the current one. See also vi-digit-or-beginning-of-line. This only works if bound to a key sequence ending in a decimal digit.

Inside a widget function, a call to this function treats the last key of the key sequence which called the widget as the digit.

neg-argument (ESC--) (unbound) (unbound)
  Changes the sign of the following argument.
universal-argument
  Multiply the argument of the next command by 4. Alternatively, if this command is followed by an integer (positive or negative), use that as the argument for the next command. Thus digits cannot be repeated using this command. For example, if this command occurs twice, followed immediately by forward-char, move forward sixteen spaces; if instead it is followed by -2, then forward-char, move backward two spaces.

Inside a widget function, if passed an argument, i.e. ‘zle universal-argument num’, the numeric argument will be set to num; this is equivalent to ‘NUMERIC=num’.

argument-base
  Use the existing numeric argument as a numeric base, which must be in the range 2 to 36 inclusive. Subsequent use of digit-argument and universal-argument will input a new numeric argument in the given base. The usual hexadecimal convention is used: the letter a or A corresponds to 10, and so on. Arguments in bases requiring digits from 10 upwards are more conveniently input with universal-argument, since ESC-a etc. are not usually bound to digit-argument.

The function can be used with a command argument inside a user-defined widget. The following code sets the base to 16 and lets the user input a hexadecimal argument until a key out of the digit range is typed:

 
zle argument-base 16
zle universal-argument

    Completion

accept-and-menu-complete
  In a menu completion, insert the current completion into the buffer, and advance to the next possible completion.
complete-word
  Attempt completion on the current word.
delete-char-or-list (^D) (unbound) (unbound)
  Delete the character under the cursor. If the cursor is at the end of the line, list possible completions for the current word.
expand-cmd-path
  Expand the current command to its full pathname.
expand-or-complete (TAB) (unbound) (TAB)
  Attempt shell expansion on the current word. If that fails, attempt completion.
expand-or-complete-prefix
  Attempt shell expansion on the current word up to cursor.
expand-history (ESC-space ESC-!) (unbound) (unbound)
  Perform history expansion on the edit buffer.
expand-word (^X*) (unbound) (unbound)
  Attempt shell expansion on the current word.
list-choices (ESC-^D) (^D =) (^D)
  List possible completions for the current word.
list-expand (^Xg ^XG) (^G) (^G)
  List the expansion of the current word.
magic-space
  Perform history expansion and insert a space into the buffer. This is intended to be bound to space.
menu-complete
  Like complete-word, except that menu completion is used. See the MENU_COMPLETE option.
menu-expand-or-complete
  Like expand-or-complete, except that menu completion is used.
reverse-menu-complete
  Perform menu completion, like menu-complete, except that if a menu completion is already in progress, move to the previous completion rather than the next.
end-of-list
  When a previous completion displayed a list below the prompt, this widget can be used to move the prompt below the list.

    Miscellaneous

accept-and-hold (ESC-A ESC-a) (unbound) (unbound)
  Push the contents of the buffer on the buffer stack and execute it.
accept-and-infer-next-history
  Execute the contents of the buffer. Then search the history list for a line matching the current one and push the event following onto the buffer stack.
accept-line (^J ^M) (^J ^M) (^J ^M)
  Finish editing the buffer. Normally this causes the buffer to be executed as a shell command.
accept-line-and-down-history (^O) (unbound) (unbound)
  Execute the current line, and push the next history event on the buffer stack.
auto-suffix-remove
  If the previous action added a suffix (space, slash, etc.) to the word on the command line, remove it. Otherwise do nothing. Removing the suffix ends any active menu completion or menu selection.

This widget is intended to be called from user-defined widgets to enforce a desired suffix-removal behavior.

auto-suffix-retain
  If the previous action added a suffix (space, slash, etc.) to the word on the command line, force it to be preserved. Otherwise do nothing. Retaining the suffix ends any active menu completion or menu selection.

This widget is intended to be called from user-defined widgets to enforce a desired suffix-preservation behavior.

beep Beep, unless the BEEP option is unset.
bracketed-paste
  This widget is invoked when text is pasted to the terminal emulator. It is not intended to be bound to actual keys but instead to the special sequence generated by the terminal emulator when text is pasted. If a numeric argument is given, shell quoting will be applied to the pasted text before it is inserted. When called from a widget function, an argument can be given to specify a variable to which pasted text is assigned.

See also the zle_bracketed_paste parameter.

vi-cmd-mode (^X^V) (unbound) (^[)
  Enter command mode; that is, select the ‘vicmd’ keymap. Yes, this is bound by default in emacs mode.
vi-caps-lock-panic
  Hang until any lowercase key is pressed. This is for vi users without the mental capacity to keep track of their caps lock key (like the author).
clear-screen (^L ESC-^L) (^L) (^L)
  Clear the screen and redraw the prompt.
deactivate-region
  Make the current region inactive. This disables vim-style visual selection mode if it is active.
describe-key-briefly
  Reads a key sequence, then prints the function bound to that sequence.
exchange-point-and-mark (^X^X) (unbound) (unbound)
  Exchange the cursor position (point) with the position of the mark. Unless a negative numeric argument is given, the region between point and mark is activated so that it can be highlighted. If a zero numeric argument is given, the region is activated but point and mark are not swapped.
execute-named-cmd (ESC-x) (:) (unbound)
  Read the name of an editor command and execute it. A restricted set of editing functions is available in the mini-buffer. Keys are looked up in the special command keymap, and if not found there in the main keymap. An interrupt signal, as defined by the stty setting, will abort the function. Note that the following always perform the same task within the executed-named-cmd environment and cannot be replaced by user defined widgets, nor can the set of functions be extended. The allowed functions are: backward-delete-char, vi-backward-delete-char, clear-screen, redisplay, quoted-insert, vi-quoted-insert, backward-kill-word, vi-backward-kill-word, kill-whole-line, vi-kill-line, backward-kill-line, list-choices, delete-char-or-list, complete-word, accept-line, expand-or-complete and expand-or-complete-prefix.

kill-region kills the last word, and vi-cmd-mode is treated the same as accept-line. The space and tab characters, if not bound to one of these functions, will complete the name and then list the possibilities if the AUTO_LIST option is set. Any other character that is not bound to self-insert or self-insert-unmeta will beep and be ignored. The bindings of the current insert mode will be used.

Currently this command may not be redefined or called by name.

execute-last-named-cmd (ESC-z) (unbound) (unbound)
  Redo the last function executed with execute-named-cmd.

Currently this command may not be redefined or called by name.

get-line (ESC-G ESC-g) (unbound) (unbound)
  Pop the top line off the buffer stack and insert it at the cursor position.
pound-insert (unbound) (#) (unbound)
  If there is no # character at the beginning of the buffer, add one to the beginning of each line. If there is one, remove a # from each line that has one. In either case, accept the current line. The INTERACTIVE_COMMENTS option must be set for this to have any usefulness.
vi-pound-insert
  If there is no # character at the beginning of the current line, add one. If there is one, remove it. The INTERACTIVE_COMMENTS option must be set for this to have any usefulness.
push-input
  Push the entire current multiline construct onto the buffer stack and return to the top-level (PS1) prompt. If the current parser construct is only a single line, this is exactly like push-line. Next time the editor starts up or is popped with get-line, the construct will be popped off the top of the buffer stack and loaded into the editing buffer.
push-line (^Q ESC-Q ESC-q) (unbound) (unbound)
  Push the current buffer onto the buffer stack and clear the buffer. Next time the editor starts up, the buffer will be popped off the top of the buffer stack and loaded into the editing buffer.
push-line-or-edit
  At the top-level (PS1) prompt, equivalent to push-line. At a secondary (PS2) prompt, move the entire current multiline construct into the editor buffer. The latter is equivalent to push-input followed by get-line.
read-command
  Only useful from a user-defined widget. A keystroke is read just as in normal operation, but instead of the command being executed the name of the command that would be executed is stored in the shell parameter REPLY. This can be used as the argument of a future zle command. If the key sequence is not bound, status 1 is returned; typically, however, REPLY is set to undefined-key to indicate a useless key sequence.
recursive-edit
  Only useful from a user-defined widget. At this point in the function, the editor regains control until one of the standard widgets which would normally cause zle to exit (typically an accept-line caused by hitting the return key) is executed. Instead, control returns to the user-defined widget. The status returned is non-zero if the return was caused by an error, but the function still continues executing and hence may tidy up. This makes it safe for the user-defined widget to alter the command line or key bindings temporarily.

The following widget, caps-lock, serves as an example.

 
self-insert-ucase() {
  LBUFFER+=${(U)KEYS[-1]}
}

integer stat

zle -N self-insert self-insert-ucase zle -A caps-lock save-caps-lock zle -A accept-line caps-lock

zle recursive-edit stat=$?

zle -A .self-insert self-insert zle -A save-caps-lock caps-lock zle -D save-caps-lock

(( stat )) && zle send-break

return $stat

This causes typed letters to be inserted capitalised until either accept-line (i.e. typically the return key) is typed or the caps-lock widget is invoked again; the later is handled by saving the old definition of caps-lock as save-caps-lock and then rebinding it to invoke accept-line. Note that an error from the recursive edit is detected as a non-zero return status and propagated by using the send-break widget.

redisplay (unbound) (^R) (^R)
  Redisplays the edit buffer.
reset-prompt (unbound) (unbound) (unbound)
  Force the prompts on both the left and right of the screen to be re-expanded, then redisplay the edit buffer. This reflects changes both to the prompt variables themselves and changes in the expansion of the values (for example, changes in time or directory, or changes to the value of variables referred to by the prompt).

Otherwise, the prompt is only expanded each time zle starts, and when the display as been interrupted by output from another part of the shell (such as a job notification) which causes the command line to be reprinted.

send-break (^G ESC-^G) (unbound) (unbound)
  Abort the current editor function, e.g. execute-named-command, or the editor itself, e.g. if you are in vared. Otherwise abort the parsing of the current line; in this case the aborted line is available in the shell variable ZLE_LINE_ABORTED. If the editor is aborted from within vared, the variable ZLE_VARED_ABORTED is set.
run-help (ESC-H ESC-h) (unbound) (unbound)
  Push the buffer onto the buffer stack, and execute the command ‘run-help cmd’, where cmd is the current command. run-help is normally aliased to man.
vi-set-buffer (unbound) (") (unbound)
  Specify a buffer to be used in the following command. There are 37 buffers that can be specified: the 26 ‘named’ buffers "a to "z, the ‘yank’ buffer "0, the nine ‘queued’ buffers "1 to "9 and the ‘black hole’ buffer "_. The named buffers can also be specified as "A to "Z.

When a buffer is specified for a cut, change or yank command, the text concerned replaces the previous contents of the specified buffer. If a named buffer is specified using a capital, the newly cut text is appended to the buffer instead of overwriting it. When using the "_ buffer, nothing happens. This can be useful for deleting text without affecting the normal registers.

If no buffer is specified for a cut or change command, "1 is used, and the contents of "1 to "8 are each shifted along one buffer; the contents of "9 is lost. If no buffer is specified for a yank command, "0 is used. Finally, a paste command without a specified buffer will paste the text from the most recent command regardless of any buffer that might have been used with that command.

When called from a widget function by the zle command, the buffer can optionally be specified with an argument. For example,

 
zle vi-set-buffer A

vi-set-mark (unbound) (m) (unbound)
  Set the specified mark at the cursor position.
set-mark-command (^@) (unbound) (unbound)
  Set the mark at the cursor position. If called with a negative numeric argument, do not set the mark but deactivate the region so that it is no longer highlighted (it is still usable for other purposes). Otherwise the region is marked as active.
spell-word (ESC-$ ESC-S ESC-s) (unbound) (unbound)
  Attempt spelling correction on the current word.
split-undo
  Breaks the undo sequence at the current change. This is useful in vi mode as changes made in insert mode are coalesced on entering command mode. Similarly, undo will normally revert as one all the changes made by a user-defined widget.
undefined-key
  This command is executed when a key sequence that is not bound to any command is typed. By default it beeps.
undo (^_ ^Xu ^X^U) (u) (unbound)
  Incrementally undo the last text modification. When called from a user-defined widget, takes an optional argument indicating a previous state of the undo history as returned by the UNDO_CHANGE_NO variable; modifications are undone until that state is reached, subject to any limit imposed by the UNDO_LIMIT_NO variable.

Note that when invoked from vi command mode, the full prior change made in insert mode is reverted, the changes having been merged when command mode was selected.

redo (unbound) (^R) (unbound)
  Incrementally redo undone text modifications.
vi-undo-change (unbound) (unbound) (unbound)
  Undo the last text modification. If repeated, redo the modification.
visual-mode (unbound) (v) (unbound)
  Toggle vim-style visual selection mode. If line-wise visual mode is currently enabled then it is changed to being character-wise. If used following an operator, it forces the subsequent movement command to be treated as a character-wise movement.
visual-line-mode (unbound) (V) (unbound)
  Toggle vim-style line-wise visual selection mode. If character-wise visual mode is currently enabled then it is changed to being line-wise. If used following an operator, it forces the subsequent movement command to be treated as a line-wise movement.
what-cursor-position (^X=) (ga) (unbound)
  Print the character under the cursor, its code as an octal, decimal and hexadecimal number, the current cursor position within the buffer and the column of the cursor in the current line.
where-is Read the name of an editor command and print the listing of key sequences that invoke the specified command. A restricted set of editing functions is available in the mini-buffer. Keys are looked up in the special command keymap, and if not found there in the main keymap.
which-command (ESC-?) (unbound) (unbound)
  Push the buffer onto the buffer stack, and execute the command ‘which-command cmd’. where cmd is the current command. which-command is normally aliased to whence.
vi-digit-or-beginning-of-line (unbound) (0) (unbound)
  If the last command executed was a digit as part of an argument, continue the argument. Otherwise, execute vi-beginning-of-line.

    Text Objects

Text objects are commands that can be used to select a block of text according to some criteria. They are a feature of the vim text editor and so are primarily intended for use with vi operators or from visual selection mode. However, they can also be used from vi-insert or emacs mode. Key bindings listed below apply to the viopp and visual keymaps.

select-a-blank-word (aW)
  Select a word including adjacent blanks, where a word is defined as a series of non-blank characters. With a numeric argument, multiple words will be selected.
select-a-shell-word (aa)
  Select the current command argument applying the normal rules for quoting.
select-a-word (aw)
  Select a word including adjacent blanks, using the normal vi-style word definition. With a numeric argument, multiple words will be selected.
select-in-blank-word (iW)
  Select a word, where a word is defined as a series of non-blank characters. With a numeric argument, multiple words will be selected.
select-in-shell-word (ia)
  Select the current command argument applying the normal rules for quoting. If the argument begins and ends with matching quote characters, these are not included in the selection.
select-in-word (iw)
  Select a word, using the normal vi-style word definition. With a numeric argument, multiple words will be selected.

CHARACTER HIGHLIGHTING

The line editor has the ability to highlight characters or regions of the line that have a particular significance. This is controlled by the array parameter zle_highlight, if it has been set by the user.

If the parameter contains the single entry none all highlighting is turned off. Note the parameter is still expected to be an array.

Otherwise each entry of the array should consist of a word indicating a context for highlighting, then a colon, then a comma-separated list of the types of highlighting to apply in that context.

The contexts available for highlighting are the following:

default
  Any text within the command line not affected by any other highlighting. Text outside the editable area of the command line is not affected.
isearch
  When one of the incremental history search widgets is active, the area of the command line matched by the search string or pattern.
region The region between the cursor (point) and the mark as set with set-mark-command. The region is only highlighted if it is active, which is the case if set-mark-command or exchange-point-and-mark has been called and the line has not been subsequently modified. The region can be deactivated by calling set-mark-command with a negative numeric argument, or reactivated by calling exchange-point-and-mark with a zero numeric argument. Note that whether or not the region is active has no effect on its use within widgets, it simply determines whether it is highlighted.
special
  Individual characters that have no direct printable representation but are shown in a special manner by the line editor. These characters are described below.
suffix This context is used in completion for characters that are marked as suffixes that will be removed if the completion ends at that point, the most obvious example being a slash (/) after a directory name. Note that suffix removal is configurable; the circumstances under which the suffix will be removed may differ for different completions.
paste Following a command to paste text, the characters that were inserted.
When region_highlight is set, the contexts that describe a region -- isearch, region, suffix, and paste -- are applied first, then region_highlight is applied, then the remaining zle_highlight contexts are applied. If a particular character is affected by multiple specifications, the last specification wins.
zle_highlight may contain additional fields for controlling how terminal sequences to change colours are output. Each of the following is followed by a colon and a string in the same form as for key bindings. This will not be necessary for the vast majority of terminals as the defaults shown in parentheses are widely used.
fg_start_code (\e[3)
  The start of the escape sequence for the foreground colour. This is followed by an ASCII digit representing the colour.
fg_default_code (9)
  The number to use instead of the colour to reset the default foreground colour.
fg_end_code (m)
  The end of the escape sequence for the foreground colour.
bg_start_code (\e[4)
  The start of the escape sequence for the background colour. This is followed by an ASCII digit representing the colour.
bg_default_code (9)
  The number to use instead of the colour to reset the default background colour.
bg_end_code (m)
  The end of the escape sequence for the background colour.
The available types of highlighting are the following. Note that not all types of highlighting are available on all terminals:
none No highlighting is applied to the given context. It is not useful for this to appear with other types of highlighting; it is used to override a default.
fg=colour
  The foreground colour should be set to colour, a decimal integer or the name of one of the eight most widely-supported colours.

Not all terminals support this and, of those that do, not all provide facilities to test the support, hence the user should decide based on the terminal type. Most terminals support the colours black, red, green, yellow, blue, magenta, cyan and white, which can be set by name. In addition. default may be used to set the terminal’s default foreground colour. Abbreviations are allowed; b or bl selects black. Some terminals may generate additional colours if the bold attribute is also present.

On recent terminals and on systems with an up-to-date terminal database the number of colours supported may be tested by the command ‘echotc Co’; if this succeeds, it indicates a limit on the number of colours which will be enforced by the line editor. The number of colours is in any case limited to 256 (i.e. the range 0 to 255).

Colour is also known as color.

bg=colour
  The background colour should be set to colour. This works similarly to the foreground colour, except the background is not usually affected by the bold attribute.
bold The characters in the given context are shown in a bold font. Not all terminals distinguish bold fonts.
standout
  The characters in the given context are shown in the terminal’s standout mode. The actual effect is specific to the terminal; on many terminals it is inverse video. On some such terminals, where the cursor does not blink it appears with standout mode negated, making it less than clear where the cursor actually is. On such terminals one of the other effects may be preferable for highlighting the region and matched search string.
underline
  The characters in the given context are shown underlined. Some terminals show the foreground in a different colour instead; in this case whitespace will not be highlighted.
The characters described above as ‘special’ are as follows. The formatting described here is used irrespective of whether the characters are highlighted:
ASCII control characters
  Control characters in the ASCII range are shown as ‘^’ followed by the base character.
Unprintable multibyte characters
  This item applies to control characters not in the ASCII range, plus other characters as follows. If the MULTIBYTE option is in effect, multibyte characters not in the ASCII character set that are reported as having zero width are treated as combining characters when the option COMBINING_CHARS is on. If the option is off, or if a character appears where a combining character is not valid, the character is treated as unprintable.

Unprintable multibyte characters are shown as a hexadecimal number between angle brackets. The number is the code point of the character in the wide character set; this may or may not be Unicode, depending on the operating system.

Invalid multibyte characters
  If the MULTIBYTE option is in effect, any sequence of one or more bytes that does not form a valid character in the current character set is treated as a series of bytes each shown as a special character. This case can be distinguished from other unprintable characters as the bytes are represented as two hexadecimal digits between angle brackets, as distinct from the four or eight digits that are used for unprintable characters that are nonetheless valid in the current character set.

Not all systems support this: for it to work, the system’s representation of wide characters must be code values from the Universal Character Set, as defined by IS0 10646 (also known as Unicode).

Wrapped double-width characters
  When a double-width character appears in the final column of a line, it is instead shown on the next line. The empty space left in the original position is highlighted as a special character.
If zle_highlight is not set or no value applies to a particular context, the defaults applied are equivalent to

 
zle_highlight=(region:standout special:standout
suffix:bold isearch:underline paste:standout)

i.e. both the region and special characters are shown in standout mode.

Within widgets, arbitrary regions may be highlighted by setting the special array parameter region_highlight; see above.

NAME

zshcompwid - zsh completion widgets

DESCRIPTION

The shell’s programmable completion mechanism can be manipulated in two ways; here the low-level features supporting the newer, function-based mechanism are defined. A complete set of shell functions based on these features is described in zshcompsys(1), and users with no interest in adding to that system (or, potentially, writing their own -- see dictionary entry for ‘hubris’) should skip the current section. The older system based on the compctl builtin command is described in zshcompctl(1).

Completion widgets are defined by the -C option to the zle builtin command provided by the zsh/zle module (see zshzle(1)). For example,

zle -C complete expand-or-complete completer

defines a widget named ‘complete’. The second argument is the name of any of the builtin widgets that handle completions: complete-word, expand-or-complete, expand-or-complete-prefix, menu-complete, menu-expand-or-complete, reverse-menu-complete, list-choices, or delete-char-or-list. Note that this will still work even if the widget in question has been re-bound.

When this newly defined widget is bound to a key using the bindkey builtin command defined in the zsh/zle module (see zshzle(1)), typing that key will call the shell function ‘completer’. This function is responsible for generating the possible matches using the builtins described below. As with other ZLE widgets, the function is called with its standard input closed.

Once the function returns, the completion code takes over control again and treats the matches in the same manner as the specified builtin widget, in this case expand-or-complete.

COMPLETION SPECIAL PARAMETERS

The parameters ZLE_REMOVE_SUFFIX_CHARS and ZLE SUFFIX_CHARS are used by the completion mechanism, but are not special. See Parameters Used By The Shell in zshparam(1).

Inside completion widgets, and any functions called from them, some parameters have special meaning; outside these functions they are not special to the shell in any way. These parameters are used to pass information between the completion code and the completion widget. Some of the builtin commands and the condition codes use or change the current values of these parameters. Any existing values will be hidden during execution of completion widgets; except for compstate, the parameters are reset on each function exit (including nested function calls from within the completion widget) to the values they had when the function was entered.

CURRENT
  This is the number of the current word, i.e. the word the cursor is currently on in the words array. Note that this value is only correct if the ksharrays option is not set.
IPREFIX
  Initially this will be set to the empty string. This parameter functions like PREFIX; it contains a string which precedes the one in PREFIX and is not considered part of the list of matches. Typically, a string is transferred from the beginning of PREFIX to the end of IPREFIX, for example:

 
IPREFIX=${PREFIX%%\=*}=
PREFIX=${PREFIX#*=}

causes the part of the prefix up to and including the first equal sign not to be treated as part of a matched string. This can be done automatically by the compset builtin, see below.

ISUFFIX
  As IPREFIX, but for a suffix that should not be considered part of the matches; note that the ISUFFIX string follows the SUFFIX string.
PREFIX Initially this will be set to the part of the current word from the beginning of the word up to the position of the cursor; it may be altered to give a common prefix for all matches.
QIPREFIX
  This parameter is read-only and contains the quoted string up to the word being completed. E.g. when completing ‘"foo’, this parameter contains the double quote. If the -q option of compset is used (see below), and the original string was ‘"foo bar’ with the cursor on the ‘bar’, this parameter contains ‘"foo ’.
QISUFFIX
  Like QIPREFIX, but containing the suffix.
SUFFIX Initially this will be set to the part of the current word from the cursor position to the end; it may be altered to give a common suffix for all matches. It is most useful when the option COMPLETE_IN_WORD is set, as otherwise the whole word on the command line is treated as a prefix.
compstate
  This is an associative array with various keys and values that the completion code uses to exchange information with the completion widget. The keys are:

all_quotes
  The -q option of the compset builtin command (see below) allows a quoted string to be broken into separate words; if the cursor is on one of those words, that word will be completed, possibly invoking ‘compset -q’ recursively. With this key it is possible to test the types of quoted strings which are currently broken into parts in this fashion. Its value contains one character for each quoting level. The characters are a single quote or a double quote for strings quoted with these characters, a dollars sign for strings quoted with $’... and a backslash for strings not starting with a quote character. The first character in the value always corresponds to the innermost quoting level.
context
  This will be set by the completion code to the overall context in which completion is attempted. Possible values are:

array_value
  when completing inside the value of an array parameter assignment; in this case the words array contains the words inside the parentheses.
brace_parameter
  when completing the name of a parameter in a parameter expansion beginning with ${. This context will also be set when completing parameter flags following ${(; the full command line argument is presented and the handler must test the value to be completed to ascertain that this is the case.
assign_parameter
  when completing the name of a parameter in a parameter assignment.
command
  when completing for a normal command (either in command position or for an argument of the command).
condition
  when completing inside a ‘[[...]]’ conditional expression; in this case the words array contains only the words inside the conditional expression.
math when completing in a mathematical environment such as a ‘((...))’ construct.
parameter
  when completing the name of a parameter in a parameter expansion beginning with $ but not ${.
redirect
  when completing after a redirection operator.
subscript
  when completing inside a parameter subscript.
value when completing the value of a parameter assignment.

exact Controls the behaviour when the REC_EXACT option is set. It will be set to accept if an exact match would be accepted, and will be unset otherwise.

If it was set when at least one match equal to the string on the line was generated, the match is accepted.

exact_string
  The string of an exact match if one was found, otherwise unset.
ignored
  The number of words that were ignored because they matched one of the patterns given with the -F option to the compadd builtin command.
insert This controls the manner in which a match is inserted into the command line. On entry to the widget function, if it is unset the command line is not to be changed; if set to unambiguous, any prefix common to all matches is to be inserted; if set to automenu-unambiguous, the common prefix is to be inserted and the next invocation of the completion code may start menu completion (due to the AUTO_MENU option being set); if set to menu or automenu menu completion will be started for the matches currently generated (in the latter case this will happen because the AUTO_MENU is set). The value may also contain the string ‘tab’ when the completion code would normally not really do completion, but only insert the TAB character.

On exit it may be set to any of the values above (where setting it to the empty string is the same as unsetting it), or to a number, in which case the match whose number is given will be inserted into the command line. Negative numbers count backward from the last match (with ‘-1’ selecting the last match) and out-of-range values are wrapped around, so that a value of zero selects the last match and a value one more than the maximum selects the first. Unless the value of this key ends in a space, the match is inserted as in a menu completion, i.e. without automatically appending a space.

Both menu and automenu may also specify the number of the match to insert, given after a colon. For example, ‘menu:2’ says to start menu completion, beginning with the second match.

Note that a value containing the substring ‘tab’ makes the matches generated be ignored and only the TAB be inserted.

Finally, it may also be set to all, which makes all matches generated be inserted into the line.

insert_positions
  When the completion system inserts an unambiguous string into the line, there may be multiple places where characters are missing or where the character inserted differs from at least one match. The value of this key contains a colon separated list of all these positions, as indexes into the command line.
last_prompt
  If this is set to a non-empty string for every match added, the completion code will move the cursor back to the previous prompt after the list of completions has been displayed. Initially this is set or unset according to the ALWAYS_LAST_PROMPT option.
list This controls whether or how the list of matches will be displayed. If it is unset or empty they will never be listed; if its value begins with list, they will always be listed; if it begins with autolist or ambiguous, they will be listed when the AUTO_LIST or LIST_AMBIGUOUS options respectively would normally cause them to be.

If the substring force appears in the value, this makes the list be shown even if there is only one match. Normally, the list would be shown only if there are at least two matches.

The value contains the substring packed if the LIST_PACKED option is set. If this substring is given for all matches added to a group, this group will show the LIST_PACKED behavior. The same is done for the LIST_ROWS_FIRST option with the substring rows.

Finally, if the value contains the string explanations, only the explanation strings, if any, will be listed and if it contains messages, only the messages (added with the -x option of compadd) will be listed. If it contains both explanations and messages both kinds of explanation strings will be listed. It will be set appropriately on entry to a completion widget and may be changed there.

list_lines
  This gives the number of lines that are needed to display the full list of completions. Note that to calculate the total number of lines to display you need to add the number of lines needed for the command line to this value, this is available as the value of the BUFFERLINES special parameter.
list_max
  Initially this is set to the value of the LISTMAX parameter. It may be set to any other value; when the widget exits this value will be used in the same way as the value of LISTMAX.
nmatches
  The number of matches generated and accepted by the completion code so far.
old_insert
  On entry to the widget this will be set to the number of the match of an old list of completions that is currently inserted into the command line. If no match has been inserted, this is unset.

As with old_list, the value of this key will only be used if it is the string keep. If it was set to this value by the widget and there was an old match inserted into the command line, this match will be kept and if the value of the insert key specifies that another match should be inserted, this will be inserted after the old one.

old_list
  This is set to yes if there is still a valid list of completions from a previous completion at the time the widget is invoked. This will usually be the case if and only if the previous editing operation was a completion widget or one of the builtin completion functions. If there is a valid list and it is also currently shown on the screen, the value of this key is shown.

After the widget has exited the value of this key is only used if it was set to keep. In this case the completion code will continue to use this old list. If the widget generated new matches, they will not be used.

parameter
  The name of the parameter when completing in a subscript or in the value of a parameter assignment.
pattern_insert
  Normally this is set to menu, which specifies that menu completion will be used whenever a set of matches was generated using pattern matching. If it is set to any other non-empty string by the user and menu completion is not selected by other option settings, the code will instead insert any common prefix for the generated matches as with normal completion.
pattern_match
  Locally controls the behaviour given by the GLOB_COMPLETE option. Initially it is set to ‘*’ if and only if the option is set. The completion widget may set it to this value, to an empty string (which has the same effect as unsetting it), or to any other non-empty string. If it is non-empty, unquoted metacharacters on the command line will be treated as patterns; if it is ‘*’, then additionally a wildcard ‘*’ is assumed at the cursor position; if it is empty or unset, metacharacters will be treated literally.

Note that the matcher specifications given to the compadd builtin command are not used if this is set to a non-empty string.

quote When completing inside quotes, this contains the quotation character (i.e. either a single quote, a double quote, or a backtick). Otherwise it is unset.
quoting
  When completing inside single quotes, this is set to the string single; inside double quotes, the string double; inside backticks, the string backtick. Otherwise it is unset.
redirect
  The redirection operator when completing in a redirection position, i.e. one of <, >, etc.
restore
  This is set to auto before a function is entered, which forces the special parameters mentioned above (words, CURRENT, PREFIX, IPREFIX, SUFFIX, and ISUFFIX) to be restored to their previous values when the function exits. If a function unsets it or sets it to any other string, they will not be restored.
to_end Specifies the occasions on which the cursor is moved to the end of a string when a match is inserted. On entry to a widget function, it may be single if this will happen when a single unambiguous match was inserted or match if it will happen any time a match is inserted (for example, by menu completion; this is likely to be the effect of the ALWAYS_TO_END option).

On exit, it may be set to single as above. It may also be set to always, or to the empty string or unset; in those cases the cursor will be moved to the end of the string always or never respectively. Any other string is treated as match.

unambiguous
  This key is read-only and will always be set to the common (unambiguous) prefix the completion code has generated for all matches added so far.
unambiguous_cursor
  This gives the position the cursor would be placed at if the common prefix in the unambiguous key were inserted, relative to the value of that key. The cursor would be placed before the character whose index is given by this key.
unambiguous_positions
  This contains all positions where characters in the unambiguous string are missing or where the character inserted differs from at least one of the matches. The positions are given as indexes into the string given by the value of the unambiguous key.
vared If completion is called while editing a line using the vared builtin, the value of this key is set to the name of the parameter given as an argument to vared. This key is only set while a vared command is active.

words This array contains the words present on the command line currently being edited.

COMPLETION BUILTIN COMMANDS

compadd [ -akqQfenUlo12C ] [ -F array ]
[-P prefix ] [ -S suffix ]
[-p hidden-prefix ] [ -s hidden-suffix ]
[-i ignored-prefix ] [ -I ignored-suffix ]
[-W file-prefix ] [ -d array ]
[-J name ] [ -V name ] [ -X explanation ] [ -x message ]
[-r remove-chars ] [ -R remove-func ]
[-D array ] [ -O array ] [ -A array ]
[-E number ]
[-M match-spec ] [ -- ] [ words ... ]
 

This builtin command can be used to add matches directly and control all the information the completion code stores with each possible match. The return status is zero if at least one match was added and non-zero if no matches were added.

The completion code breaks the string to complete into seven fields in the order:

 
<ipre><apre><hpre><word><hsuf><asuf><isuf>

The first field is an ignored prefix taken from the command line, the contents of the IPREFIX parameter plus the string given with the -i option. With the -U option, only the string from the -i option is used. The field <apre> is an optional prefix string given with the -P option. The <hpre> field is a string that is considered part of the match but that should not be shown when listing completions, given with the -p option; for example, functions that do filename generation might specify a common path prefix this way. <word> is the part of the match that should appear in the list of completions, i.e. one of the words given at the end of the compadd command line. The suffixes <hsuf>, <asuf> and <isuf> correspond to the prefixes <hpre>, <apre> and <ipre> and are given by the options -s, -S and -I, respectively.

The supported flags are:

-P prefix
  This gives a string to be inserted before the given words. The string given is not considered as part of the match and any shell metacharacters in it will not be quoted when the string is inserted.
-S suffix
  Like -P, but gives a string to be inserted after the match.
-p hidden-prefix
  This gives a string that should be inserted into the command line before the match but that should not appear in the list of matches. Unless the -U option is given, this string must be matched as part of the string on the command line.
-s hidden-suffix
  Like ‘-p’, but gives a string to insert after the match.
-i ignored-prefix
  This gives a string to insert into the command line just before any string given with the ‘-P’ option. Without ‘-P’ the string is inserted before the string given with ‘-p’ or directly before the match.
-I ignored-suffix
  Like -i, but gives an ignored suffix.
-a With this flag the words are taken as names of arrays and the possible matches are their values. If only some elements of the arrays are needed, the words may also contain subscripts, as in ‘foo[2,-1]’.
-k With this flag the words are taken as names of associative arrays and the possible matches are their keys. As for -a, the words may also contain subscripts, as in ‘foo[(R)*bar*]’.
-d array This adds per-match display strings. The array should contain one element per word given. The completion code will then display the first element instead of the first word, and so on. The array may be given as the name of an array parameter or directly as a space-separated list of words in parentheses.

If there are fewer display strings than words, the leftover words will be displayed unchanged and if there are more display strings than words, the leftover display strings will be silently ignored.

-l This option only has an effect if used together with the -d option. If it is given, the display strings are listed one per line, not arrayed in columns.
-o This option only has an effect if used together with the -d option. If it is given, the order of the output is determined by the match strings; otherwise it is determined by the display strings (i.e. the strings given by the -d option).
-J name Gives the name of the group of matches the words should be stored in.
-V name Like -J but naming an unsorted group. These are in a different name space than groups created with the -J flag.
-1 If given together with the -V option, makes only consecutive duplicates in the group be removed. If combined with the -J option, this has no visible effect. Note that groups with and without this flag are in different name spaces.
-2 If given together with the -J or -V option, makes all duplicates be kept. Again, groups with and without this flag are in different name spaces.
-X explanation
  The explanation string will be printed with the list of matches, above the group currently selected.
-x message
  Like -X, but the message will be printed even if there are no matches in the group.
-q The suffix given with -S will be automatically removed if the next character typed is a blank or does not insert anything, or if the suffix consists of only one character and the next character typed is the same character.
-r remove-chars
  This is a more versatile form of the -q option. The suffix given with -S or the slash automatically added after completing directories will be automatically removed if the next character typed inserts one of the characters given in the remove-chars. This string is parsed as a characters class and understands the backslash sequences used by the print command. For example, ‘-r "a-z\t"’ removes the suffix if the next character typed inserts a lower case character or a TAB, and ‘-r "^0-9"’ removes the suffix if the next character typed inserts anything but a digit. One extra backslash sequence is understood in this string: ‘\-’ stands for all characters that insert nothing. Thus ‘-S "=" -q’ is the same as ‘-S "=" -r "= \t\n\-"’.

This option may also be used without the -S option; then any automatically added space will be removed when one of the characters in the list is typed.

-R remove-func
  This is another form of the -r option. When a suffix has been inserted and the completion accepted, the function remove-func will be called after the next character typed. It is passed the length of the suffix as an argument and can use the special parameters available in ordinary (non-completion) zle widgets (see zshzle(1)) to analyse and modify the command line.
-f If this flag is given, all of the matches built from words are marked as being the names of files. They are not required to be actual filenames, but if they are, and the option LIST_TYPES is set, the characters describing the types of the files in the completion lists will be shown. This also forces a slash to be added when the name of a directory is completed.
-e This flag can be used to tell the completion code that the matches added are parameter names for a parameter expansion. This will make the AUTO_PARAM_SLASH and AUTO_PARAM_KEYS options be used for the matches.
-W file-prefix
  This string is a pathname that will be prepended to each of the matches formed by the given words together with any prefix specified by the -p option to form a complete filename for testing. Hence it is only useful if combined with the -f flag, as the tests will not otherwise be performed.
-F array Specifies an array containing patterns. Words matching one of these patterns are ignored, i.e. not considered to be possible matches.

The array may be the name of an array parameter or a list of literal patterns enclosed in parentheses and quoted, as in ‘-F "(*?.o *?.h)"’. If the name of an array is given, the elements of the array are taken as the patterns.

-Q This flag instructs the completion code not to quote any metacharacters in the words when inserting them into the command line.
-M match-spec
  This gives local match specifications as described below in the section ‘Completion Matching Control’. This option may be given more than once. In this case all match-specs given are concatenated with spaces between them to form the specification string to use. Note that they will only be used if the -U option is not given.
-n Specifies that the words added are to be used as possible matches, but are not to appear in the completion listing.
-U If this flag is given, all words given will be accepted and no matching will be done by the completion code. Normally this is used in functions that do the matching themselves.
-O array If this option is given, the words are not added to the set of possible completions. Instead, matching is done as usual and all of the words given as arguments that match the string on the command line will be stored in the array parameter whose name is given as array.
-A array As the -O option, except that instead of those of the words which match being stored in array, the strings generated internally by the completion code are stored. For example, with a matching specification of ‘-M "L:|no="’, the string ‘nof’ on the command line and the string ‘foo’ as one of the words, this option stores the string ‘nofoo’ in the array, whereas the -O option stores the ‘foo’ originally given.
-D array As with -O, the words are not added to the set of possible completions. Instead, the completion code tests whether each word in turn matches what is on the line. If the nth word does not match, the nth element of the array is removed. Elements for which the corresponding word is matched are retained.
-C This option adds a special match which expands to all other matches when inserted into the line, even those that are added after this option is used. Together with the -d option it is possible to specify a string that should be displayed in the list for this special match. If no string is given, it will be shown as a string containing the strings that would be inserted for the other matches, truncated to the width of the screen.
-E number
  This option adds number empty matches after the words have been added. An empty match takes up space in completion listings but will never be inserted in the line and can’t be selected with menu completion or menu selection. This makes empty matches only useful to format completion lists and to make explanatory string be shown in completion lists (since empty matches can be given display strings with the -d option). And because all but one empty string would otherwise be removed, this option implies the -V and -2 options (even if an explicit -J option is given). This can be important to note as it affects the name space into which matches are added.
-
--
This flag ends the list of flags and options. All arguments after it will be taken as the words to use as matches even if they begin with hyphens.
Except for the -M flag, if any of these flags is given more than once, the first one (and its argument) will be used.

compset -p number
compset -P [ number ] pattern
compset -s number
compset -S [ number ] pattern
compset -n begin [ end ]
compset -N beg-pat [ end-pat ]
compset -q
  This command simplifies modification of the special parameters, while its return status allows tests on them to be carried out.

The options are:

-p number
  If the contents of the PREFIX parameter is longer than number characters, the first number characters are removed from it and appended to the contents of the IPREFIX parameter.
-P [ number ] pattern
  If the value of the PREFIX parameter begins with anything that matches the pattern, the matched portion is removed from PREFIX and appended to IPREFIX.

Without the optional number, the longest match is taken, but if number is given, anything up to the numberth match is moved. If the number is negative, the numberth longest match is moved. For example, if PREFIX contains the string ‘a=b=c’, then compset -P ’*\=’ will move the string ‘a=b=’ into the IPREFIX parameter, but compset -P 1 ’*\=’ will move only the string ‘a=’.

-s number
  As -p, but transfer the last number characters from the value of SUFFIX to the front of the value of ISUFFIX.
-S [ number ] pattern
  As -P, but match the last portion of SUFFIX and transfer the matched portion to the front of the value of ISUFFIX.
-n begin [ end ]
  If the current word position as specified by the parameter CURRENT is greater than or equal to begin, anything up to the beginth word is removed from the words array and the value of the parameter CURRENT is decremented by begin.

If the optional end is given, the modification is done only if the current word position is also less than or equal to end. In this case, the words from position end onwards are also removed from the words array.

Both begin and end may be negative to count backwards from the last element of the words array.

-N beg-pat [ end-pat ]
  If one of the elements of the words array before the one at the index given by the value of the parameter CURRENT matches the pattern beg-pat, all elements up to and including the matching one are removed from the words array and the value of CURRENT is changed to point to the same word in the changed array.

If the optional pattern end-pat is also given, and there is an element in the words array matching this pattern, the parameters are modified only if the index of this word is higher than the one given by the CURRENT parameter (so that the matching word has to be after the cursor). In this case, the words starting with the one matching end-pat are also removed from the words array. If words contains no word matching end-pat, the testing and modification is performed as if it were not given.

-q The word currently being completed is split on spaces into separate words, respecting the usual shell quoting conventions. The resulting words are stored in the words array, and CURRENT, PREFIX, SUFFIX, QIPREFIX, and QISUFFIX are modified to reflect the word part that is completed.
In all the above cases the return status is zero if the test succeeded and the parameters were modified and non-zero otherwise. This allows one to use this builtin in tests such as:

 
if compset -P ’*\=’; then ...

This forces anything up to and including the last equal sign to be ignored by the completion code.

compcall [ -TD ]
  This allows the use of completions defined with the compctl builtin from within completion widgets. The list of matches will be generated as if one of the non-widget completion functions (complete-word, etc.) had been called, except that only compctls given for specific commands are used. To force the code to try completions defined with the -T option of compctl and/or the default completion (whether defined by compctl -D or the builtin default) in the appropriate places, the -T and/or -D flags can be passed to compcall.

The return status can be used to test if a matching compctl definition was found. It is non-zero if a compctl was found and zero otherwise.

Note that this builtin is defined by the zsh/compctl module.

COMPLETION CONDITION CODES

The following additional condition codes for use within the [[ ... ]] construct are available in completion widgets. These work on the special parameters. All of these tests can also be performed by the compset builtin, but in the case of the condition codes the contents of the special parameters are not modified.

-prefix [ number ] pattern
  true if the test for the -P option of compset would succeed.
-suffix [ number ] pattern
  true if the test for the -S option of compset would succeed.
-after beg-pat
  true if the test of the -N option with only the beg-pat given would succeed.
-between beg-pat end-pat
  true if the test for the -N option with both patterns would succeed.

COMPLETION MATCHING CONTROL

It is possible by use of the -M option of the compadd builtin command to specify how the characters in the string to be completed (referred to here as the command line) map onto the characters in the list of matches produced by the completion code (referred to here as the trial completions). Note that this is not used if the command line contains a glob pattern and the GLOB_COMPLETE option is set or the pattern_match of the compstate special association is set to a non-empty string.

The match-spec given as the argument to the -M option (see ‘Completion Builtin Commands’ above) consists of one or more matching descriptions separated by whitespace. Each description consists of a letter followed by a colon and then the patterns describing which character sequences on the line match which character sequences in the trial completion. Any sequence of characters not handled in this fashion must match exactly, as usual.

The forms of match-spec understood are as follows. In each case, the form with an upper case initial character retains the string already typed on the command line as the final result of completion, while with a lower case initial character the string on the command line is changed into the corresponding part of the trial completion.

m:lpat=tpat
M:lpat=tpat
  Here, lpat is a pattern that matches on the command line, corresponding to tpat which matches in the trial completion.
l:lanchor|lpat=tpat
L:lanchor|lpat=tpat
l:lanchor||ranchor=tpat
L:lanchor||ranchor=tpat
b:lpat=tpat
B:lpat=tpat
  These letters are for patterns that are anchored by another pattern on the left side. Matching for lpat and tpat is as for m and M, but the pattern lpat matched on the command line must be preceded by the pattern lanchor. The lanchor can be blank to anchor the match to the start of the command line string; otherwise the anchor can occur anywhere, but must match in both the command line and trial completion strings.

If no lpat is given but a ranchor is, this matches the gap between substrings matched by lanchor and ranchor. Unlike lanchor, the ranchor only needs to match the trial completion string.

The b and B forms are similar to l and L with an empty anchor, but need to match only the beginning of the word on the command line or trial completion, respectively.

r:lpat|ranchor=tpat
R:lpat|ranchor=tpat
r:lanchor||ranchor=tpat
R:lanchor||ranchor=tpat
e:lpat=tpat
E:lpat=tpat
  As l, L, b and B, with the difference that the command line and trial completion patterns are anchored on the right side. Here an empty ranchor and the e and E forms force the match to the end of the command line or trial completion string.
Each lpat, tpat or anchor is either an empty string or consists of a sequence of literal characters (which may be quoted with a backslash), question marks, character classes, and correspondence classes; ordinary shell patterns are not used. Literal characters match only themselves, question marks match any character, and character classes are formed as for globbing and match any character in the given set.
Correspondence classes are defined like character classes, but with two differences: they are delimited by a pair of braces, and negated classes are not allowed, so the characters ! and ^ have no special meaning directly after the opening brace. They indicate that a range of characters on the line match a range of characters in the trial completion, but (unlike ordinary character classes) paired according to the corresponding position in the sequence. For example, to make any ASCII lower case letter on the line match the corresponding upper case letter in the trial completion, you can use ‘m:{a-z}={A-Z}’ (however, see below for the recommended form for this). More than one pair of classes can occur, in which case the first class before the = corresponds to the first after it, and so on. If one side has more such classes than the other side, the superfluous classes behave like normal character classes. In anchor patterns correspondence classes also behave like normal character classes.
The standard ‘[:name:]’ forms described for standard shell patterns (see the section FILENAME GENERATION in zshexpn(1)) may appear in correspondence classes as well as normal character classes. The only special behaviour in correspondence classes is if the form on the left and the form on the right are each one of [:upper:], [:lower:]. In these cases the character in the word and the character on the line must be the same up to a difference in case. Hence to make any lower case character on the line match the corresponding upper case character in the trial completion you can use ‘m:{[:lower:]}={[:upper:]}’. Although the matching system does not yet handle multibyte characters, this is likely to be a future extension, at which point this syntax will handle arbitrary alphabets; hence this form, rather than the use of explicit ranges, is the recommended form. In other cases ‘[:name:]’ forms are allowed. If the two forms on the left and right are the same, the characters must match exactly. In remaining cases, the corresponding tests are applied to both characters, but they are not otherwise constrained; any matching character in one set goes with any matching character in the other set: this is equivalent to the behaviour of ordinary character classes.
The pattern tpat may also be one or two stars, ‘*’ or ‘**’. This means that the pattern on the command line can match any number of characters in the trial completion. In this case the pattern must be anchored (on either side); in the case of a single star, the anchor then determines how much of the trial completion is to be included -- only the characters up to the next appearance of the anchor will be matched. With two stars, substrings matched by the anchor can be matched, too.
Examples:
The keys of the options association defined by the parameter module are the option names in all-lower-case form, without underscores, and without the optional no at the beginning even though the builtins setopt and unsetopt understand option names with upper case letters, underscores, and the optional no. The following alters the matching rules so that the prefix no and any underscore are ignored when trying to match the trial completions generated and upper case letters on the line match the corresponding lower case letters in the words:

 
compadd -M ’L:|[nN][oO]= M:_= M:{[:upper:]}={[:lower:]}’ - \
  ${(k)options} 

The first part says that the pattern ‘[nN][oO]’ at the beginning (the empty anchor before the pipe symbol) of the string on the line matches the empty string in the list of words generated by completion, so it will be ignored if present. The second part does the same for an underscore anywhere in the command line string, and the third part uses correspondence classes so that any upper case letter on the line matches the corresponding lower case letter in the word. The use of the upper case forms of the specification characters (L and M) guarantees that what has already been typed on the command line (in particular the prefix no) will not be deleted.
Note that the use of L in the first part means that it matches only when at the beginning of both the command line string and the trial completion. I.e., the string ‘_NO_f’ would not be completed to ‘_NO_foo’, nor would ‘NONO_f’ be completed to ‘NONO_foo’ because of the leading underscore or the second ‘NO’ on the line which makes the pattern fail even though they are otherwise ignored. To fix this, one would use ‘B:[nN][oO]=’ instead of the first part. As described above, this matches at the beginning of the trial completion, independent of other characters or substrings at the beginning of the command line word which are ignored by the same or other match-specs.
The second example makes completion case insensitive. This is just the same as in the option example, except here we wish to retain the characters in the list of completions:

 
compadd -M ’m:{[:lower:]}={[:upper:]}’ ... 

This makes lower case letters match their upper case counterparts. To make upper case letters match the lower case forms as well:

 
compadd -M ’m:{[:lower:][:upper:]}={[:upper:][:lower:]}’ ... 

A nice example for the use of * patterns is partial word completion. Sometimes you would like to make strings like ‘c.s.u’ complete to strings like ‘comp.source.unix’, i.e. the word on the command line consists of multiple parts, separated by a dot in this example, where each part should be completed separately -- note, however, that the case where each part of the word, i.e. ‘comp’, ‘source’ and ‘unix’ in this example, is to be completed from separate sets of matches is a different problem to be solved by the implementation of the completion widget. The example can be handled by:

 
compadd -M ’r:|.=* r:|=*’ \
  - comp.sources.unix comp.sources.misc ...

The first specification says that lpat is the empty string, while anchor is a dot; tpat is *, so this can match anything except for the ‘.’ from the anchor in the trial completion word. So in ‘c.s.u’, the matcher sees ‘c’, followed by the empty string, followed by the anchor ‘.’, and likewise for the second dot, and replaces the empty strings before the anchors, giving ‘c[omp].s[ources].u[nix]’, where the last part of the completion is just as normal.
With the pattern shown above, the string ‘c.u’ could not be completed to ‘comp.sources.unix’ because the single star means that no dot (matched by the anchor) can be skipped. By using two stars as in ‘r:|.=**’, however, ‘c.u’ could be completed to ‘comp.sources.unix’. This also shows that in some cases, especially if the anchor is a real pattern, like a character class, the form with two stars may result in more matches than one would like.
The second specification is needed to make this work when the cursor is in the middle of the string on the command line and the option COMPLETE_IN_WORD is set. In this case the completion code would normally try to match trial completions that end with the string as typed so far, i.e. it will only insert new characters at the cursor position rather than at the end. However in our example we would like the code to recognise matches which contain extra characters after the string on the line (the ‘nix’ in the example). Hence we say that the empty string at the end of the string on the line matches any characters at the end of the trial completion.
More generally, the specification

 
compadd -M ’r:|[.,_-]=* r:|=*’ ... 

allows one to complete words with abbreviations before any of the characters in the square brackets. For example, to complete veryverylongfile.c rather than veryverylongheader.h with the above in effect, you can just type very.c before attempting completion.
The specifications with both a left and a right anchor are useful to complete partial words whose parts are not separated by some special character. For example, in some places strings have to be completed that are formed ‘LikeThis’ (i.e. the separate parts are determined by a leading upper case letter) or maybe one has to complete strings with trailing numbers. Here one could use the simple form with only one anchor as in:

 
compadd -M ’r:|[[:upper:]0-9]=* r:|=*’ LikeTHIS FooHoo 5foo123 5bar234

But with this, the string ‘H’ would neither complete to ‘FooHoo’ nor to ‘LikeTHIS’ because in each case there is an upper case letter before the ‘H’ and that is matched by the anchor. Likewise, a ‘2’ would not be completed. In both cases this could be changed by using ‘r:|[[:upper:]0-9]=**’, but then ‘H’ completes to both ‘LikeTHIS’ and ‘FooHoo’ and a ‘2’ matches the other strings because characters can be inserted before every upper case letter and digit. To avoid this one would use:

 
compadd -M ’r:[^[:upper:]0-9]||[[:upper:]0-9]=** r:|=*’ \
    LikeTHIS FooHoo foo123 bar234

By using these two anchors, a ‘H’ matches only upper case ‘H’s that are immediately preceded by something matching the left anchor ‘[^[:upper:]0-9]’. The effect is, of course, that ‘H’ matches only the string ‘FooHoo’, a ‘2’ matches only ‘bar234’ and so on.

When using the completion system (see zshcompsys(1)), users can define match specifications that are to be used for specific contexts by using the matcher and matcher-list styles. The values for the latter will be used everywhere.

COMPLETION WIDGET EXAMPLE

The first step is to define the widget:

zle -C complete complete-word complete-files

Then the widget can be bound to a key using the bindkey builtin command:

bindkey ’^X\t’ complete

After that the shell function complete-files will be invoked after typing control-X and TAB. The function should then generate the matches, e.g.:

complete-files () { compadd - * }

This function will complete files in the current directory matching the current word.

NAME

zshcompsys - zsh completion system

DESCRIPTION

This describes the shell code for the ‘new’ completion system, referred to as compsys. It is written in shell functions based on the features described in zshcompwid(1).

The features are contextual, sensitive to the point at which completion is started. Many completions are already provided. For this reason, a user can perform a great many tasks without knowing any details beyond how to initialize the system, which is described below in INITIALIZATION.

The context that decides what completion is to be performed may be
o an argument or option position: these describe the position on the command line at which completion is requested. For example ‘first argument to rmdir, the word being completed names a directory’;

o a special context, denoting an element in the shell’s syntax. For example ‘a word in command position’ or ‘an array subscript’.

A full context specification contains other elements, as we shall describe.
Besides commands names and contexts, the system employs two more concepts, styles and tags. These provide ways for the user to configure the system’s behaviour.
Tags play a dual role. They serve as a classification system for the matches, typically indicating a class of object that the user may need to distinguish. For example, when completing arguments of the ls command the user may prefer to try files before directories, so both of these are tags. They also appear as the rightmost element in a context specification.
Styles modify various operations of the completion system, such as output formatting, but also what kinds of completers are used (and in what order), or which tags are examined. Styles may accept arguments and are manipulated using the zstyle command described in see zshmodules(1).
In summary, tags describe what the completion objects are, and style how they are to be completed. At various points of execution, the completion system checks what styles and/or tags are defined for the current context, and uses that to modify its behavior. The full description of context handling, which determines how tags and other elements of the context influence the behaviour of styles, is described below in COMPLETION SYSTEM CONFIGURATION.
When a completion is requested, a dispatcher function is called; see the description of _main_complete in the list of control functions below. This dispatcher decides which function should be called to produce the completions, and calls it. The result is passed to one or more completers, functions that implement individual completion strategies: simple completion, error correction, completion with error correction, menu selection, etc.
More generally, the shell functions contained in the completion system are of two types:
o those beginning ‘comp’ are to be called directly; there are only a few of these;

o those beginning ‘_’ are called by the completion code. The shell functions of this set, which implement completion behaviour and may be bound to keystrokes, are referred to as ‘widgets’. These proliferate as new completions are required.

INITIALIZATION

If the system was installed completely, it should be enough to call the shell function compinit from your initialization file; see the next section. However, the function compinstall can be run by a user to configure various aspects of the completion system.

Usually, compinstall will insert code into .zshrc, although if that is not writable it will save it in another file and tell you that file’s location. Note that it is up to you to make sure that the lines added to .zshrc are actually run; you may, for example, need to move them to an earlier place in the file if .zshrc usually returns early. So long as you keep them all together (including the comment lines at the start and finish), you can rerun compinstall and it will correctly locate and modify these lines. Note, however, that any code you add to this section by hand is likely to be lost if you rerun compinstall, although lines using the command ‘zstyle’ should be gracefully handled.

The new code will take effect next time you start the shell, or run .zshrc by hand; there is also an option to make them take effect immediately. However, if compinstall has removed definitions, you will need to restart the shell to see the changes.

To run compinstall you will need to make sure it is in a directory mentioned in your fpath parameter, which should already be the case if zsh was properly configured as long as your startup files do not remove the appropriate directories from fpath. Then it must be autoloaded (‘autoload -U compinstall’ is recommended). You can abort the installation any time you are being prompted for information, and your .zshrc will not be altered at all; changes only take place right at the end, where you are specifically asked for confirmation.

    Use of compinit

This section describes the use of compinit to initialize completion for the current session when called directly; if you have run compinstall it will be called automatically from your .zshrc.

To initialize the system, the function compinit should be in a directory mentioned in the fpath parameter, and should be autoloaded (‘autoload -U compinit’ is recommended), and then run simply as ‘compinit’. This will define a few utility functions, arrange for all the necessary shell functions to be autoloaded, and will then re-define all widgets that do completion to use the new system. If you use the menu-select widget, which is part of the zsh/complist module, you should make sure that that module is loaded before the call to compinit so that that widget is also re-defined. If completion styles (see below) are set up to perform expansion as well as completion by default, and the TAB key is bound to expand-or-complete, compinit will rebind it to complete-word; this is necessary to use the correct form of expansion.

Should you need to use the original completion commands, you can still bind keys to the old widgets by putting a ‘.’ in front of the widget name, e.g. ‘.expand-or-complete’.

To speed up the running of compinit, it can be made to produce a dumped configuration that will be read in on future invocations; this is the default, but can be turned off by calling compinit with the option -D. The dumped file is .zcompdump in the same directory as the startup files (i.e. $ZDOTDIR or $HOME); alternatively, an explicit file name can be given by ‘compinit -d dumpfile’. The next invocation of compinit will read the dumped file instead of performing a full initialization.

If the number of completion files changes, compinit will recognise this and produce a new dump file. However, if the name of a function or the arguments in the first line of a #compdef function (as described below) change, it is easiest to delete the dump file by hand so that compinit will re-create it the next time it is run. The check performed to see if there are new functions can be omitted by giving the option -C. In this case the dump file will only be created if there isn’t one already.

The dumping is actually done by another function, compdump, but you will only need to run this yourself if you change the configuration (e.g. using compdef) and then want to dump the new one. The name of the old dumped file will be remembered for this purpose.

If the parameter _compdir is set, compinit uses it as a directory where completion functions can be found; this is only necessary if they are not already in the function search path.

For security reasons compinit also checks if the completion system would use files not owned by root or by the current user, or files in directories that are world- or group-writable or that are not owned by root or by the current user. If such files or directories are found, compinit will ask if the completion system should really be used. To avoid these tests and make all files found be used without asking, use the option -u, and to make compinit silently ignore all insecure files and directories use the option -i. This security check is skipped entirely when the -C option is given.

The security check can be retried at any time by running the function compaudit. This is the same check used by compinit, but when it is executed directly any changes to fpath are made local to the function so they do not persist. The directories to be checked may be passed as arguments; if none are given, compaudit uses fpath and _compdir to find completion system directories, adding missing ones to fpath as necessary. To force a check of exactly the directories currently named in fpath, set _compdir to an empty string before calling compaudit or compinit.

The function bashcompinit provides compatibility with bash’s programmable completion system. When run it will define the functions, compgen and complete which correspond to the bash builtins with the same names. It will then be possible to use completion specifications and functions written for bash.

    Autoloaded files

The convention for autoloaded functions used in completion is that they start with an underscore; as already mentioned, the fpath/FPATH parameter must contain the directory in which they are stored. If zsh was properly installed on your system, then fpath/FPATH automatically contains the required directories for the standard functions.

For incomplete installations, if compinit does not find enough files beginning with an underscore (fewer than twenty) in the search path, it will try to find more by adding the directory _compdir to the search path. If that directory has a subdirectory named Base, all subdirectories will be added to the path. Furthermore, if the subdirectory Base has a subdirectory named Core, compinit will add all subdirectories of the subdirectories to the path: this allows the functions to be in the same format as in the zsh source distribution.

When compinit is run, it searches all such files accessible via fpath/FPATH and reads the first line of each of them. This line should contain one of the tags described below. Files whose first line does not start with one of these tags are not considered to be part of the completion system and will not be treated specially.

The tags are:

#compdef name ... [ -{p|P} pattern ... [ -N name ... ] ]
  The file will be made autoloadable and the function defined in it will be called when completing names, each of which is either the name of a command whose arguments are to be completed or one of a number of special contexts in the form -context- described below.

Each name may also be of the form ‘cmd=service’. When completing the command cmd, the function typically behaves as if the command (or special context) service was being completed instead. This provides a way of altering the behaviour of functions that can perform many different completions. It is implemented by setting the parameter $service when calling the function; the function may choose to interpret this how it wishes, and simpler functions will probably ignore it.

If the #compdef line contains one of the options -p or -P, the words following are taken to be patterns. The function will be called when completion is attempted for a command or context that matches one of the patterns. The options -p and -P are used to specify patterns to be tried before or after other completions respectively. Hence -P may be used to specify default actions.

The option -N is used after a list following -p or -P; it specifies that remaining words no longer define patterns. It is possible to toggle between the three options as many times as necessary.

#compdef -k style key-sequence ...
  This option creates a widget behaving like the builtin widget style and binds it to the given key-sequences, if any. The style must be one of the builtin widgets that perform completion, namely complete-word, delete-char-or-list, expand-or-complete, expand-or-complete-prefix, list-choices, menu-complete, menu-expand-or-complete, or reverse-menu-complete. If the zsh/complist module is loaded (see zshmodules(1)) the widget menu-select is also available.

When one of the key-sequences is typed, the function in the file will be invoked to generate the matches. Note that a key will not be re-bound if it already was (that is, was bound to something other than undefined-key). The widget created has the same name as the file and can be bound to any other keys using bindkey as usual.

#compdef -K widget-name style key-sequence [ name style seq ... ]
  This is similar to -k except that only one key-sequence argument may be given for each widget-name style pair. However, the entire set of three arguments may be repeated with a different set of arguments. Note in particular that the widget-name must be distinct in each set. If it does not begin with ‘_’ this will be added. The widget-name should not clash with the name of any existing widget: names based on the name of the function are most useful. For example,

 
#compdef -K _foo_complete complete-word "^X^C" \
  _foo_list list-choices "^X^D"

(all on one line) defines a widget _foo_complete for completion, bound to ‘^X^C’, and a widget _foo_list for listing, bound to ‘^X^D’.

#autoload [ options ]
  Functions with the #autoload tag are marked for autoloading but are not otherwise treated specially. Typically they are to be called from within one of the completion functions. Any options supplied will be passed to the autoload builtin; a typical use is +X to force the function to be loaded immediately. Note that the -U and -z flags are always added implicitly.
The # is part of the tag name and no white space is allowed after it. The #compdef tags use the compdef function described below; the main difference is that the name of the function is supplied implicitly.
The special contexts for which completion functions can be defined are:
-array-value-
  The right hand side of an array-assignment (‘name=(...)’)
-brace-parameter-
  The name of a parameter expansion within braces (‘${...}’)
-assign-parameter-
  The name of a parameter in an assignment, i.e. on the left hand side of an ‘=
-command-
  A word in command position
-condition-
  A word inside a condition (‘[[...]]’)
-default-
  Any word for which no other completion is defined
-equal- A word beginning with an equals sign
-first- This is tried before any other completion function. The function called may set the _compskip parameter to one of various values: all: no further completion is attempted; a string containing the substring patterns: no pattern completion functions will be called; a string containing default: the function for the ‘-default-’ context will not be called, but functions defined for commands will be.
-math- Inside mathematical contexts, such as ‘((...))
-parameter-
  The name of a parameter expansion (‘$...’)
-redirect-
  The word after a redirection operator.
-subscript-
  The contents of a parameter subscript.
-tilde- After an initial tilde (‘~’), but before the first slash in the word.
-value- On the right hand side of an assignment.
Default implementations are supplied for each of these contexts. In most cases the context -context- is implemented by a corresponding function _context, for example the context ‘-tilde-’ and the function ‘_tilde’).
The contexts -redirect- and -value- allow extra context-specific information. (Internally, this is handled by the functions for each context calling the function _dispatch.) The extra information is added separated by commas.
For the -redirect- context, the extra information is in the form ‘-redirect-,op,command’, where op is the redirection operator and command is the name of the command on the line. If there is no command on the line yet, the command field will be empty.
For the -value- context, the form is ‘-value-,name,command’, where name is the name of the parameter on the left hand side of the assignment. In the case of elements of an associative array, for example ‘assoc=(key <TAB>’, name is expanded to ‘name-key’. In certain special contexts, such as completing after ‘make CFLAGS=’, the command part gives the name of the command, here make; otherwise it is empty.
It is not necessary to define fully specific completions as the functions provided will try to generate completions by progressively replacing the elements with ‘-default-’. For example, when completing after ‘foo=<TAB>’, _value will try the names ‘-value-,foo,’ (note the empty command part), ‘-value-,foo,-default-’ and‘-value-,-default-,-default-’, in that order, until it finds a function to handle the context.
As an example:

 
compdef ’_files -g "*.log"’ ’-redirect-,2>,-default-’

completes files matching ‘*.log’ after ‘2> <TAB>’ for any command with no more specific handler defined.
Also:

 
compdef _foo -value-,-default-,-default-

specifies that _foo provides completions for the values of parameters for which no special function has been defined. This is usually handled by the function _value itself.
The same lookup rules are used when looking up styles (as described below); for example

 
zstyle ’:completion:*:*:-redirect-,2>,*:*’ file-patterns ’*.log’

is another way to make completion after ‘2> <TAB>’ complete files matching ‘*.log’.

    Functions

The following function is defined by compinit and may be called directly.

compdef [ -ane ] function name ... [ -{p|P} pattern ... [ -N name ...]]
compdef -d name ...
compdef -k [ -an ] function style key-sequence [ key-sequence ... ]
compdef -K [ -an ] function name style key-seq [ name style seq ... ]
  The first form defines the function to call for completion in the given contexts as described for the #compdef tag above.

Alternatively, all the arguments may have the form ‘cmd=service’. Here service should already have been defined by ‘cmd1=service’ lines in #compdef files, as described above. The argument for cmd will be completed in the same way as service.

The function argument may alternatively be a string containing almost any shell code. If the string contains an equal sign, the above will take precedence. The option -e may be used to specify the first argument is to be evaluated as shell code even if it contains an equal sign. The string will be executed using the eval builtin command to generate completions. This provides a way of avoiding having to define a new completion function. For example, to complete files ending in ‘.h’ as arguments to the command foo:

 
compdef ’_files -g "*.h"’ foo

The option -n prevents any completions already defined for the command or context from being overwritten.

The option -d deletes any completion defined for the command or contexts listed.

The names may also contain -p, -P and -N options as described for the #compdef tag. The effect on the argument list is identical, switching between definitions of patterns tried initially, patterns tried finally, and normal commands and contexts.

The parameter $_compskip may be set by any function defined for a pattern context. If it is set to a value containing the substring ‘patterns’ none of the pattern-functions will be called; if it is set to a value containing the substring ‘all’, no other function will be called.

The form with -k defines a widget with the same name as the function that will be called for each of the key-sequences; this is like the #compdef -k tag. The function should generate the completions needed and will otherwise behave like the builtin widget whose name is given as the style argument. The widgets usable for this are: complete-word, delete-char-or-list, expand-or-complete, expand-or-complete-prefix, list-choices, menu-complete, menu-expand-or-complete, and reverse-menu-complete, as well as menu-select if the zsh/complist module is loaded. The option -n prevents the key being bound if it is already to bound to something other than undefined-key.

The form with -K is similar and defines multiple widgets based on the same function, each of which requires the set of three arguments name, style and key-sequence, where the latter two are as for -k and the first must be a unique widget name beginning with an underscore.

Wherever applicable, the -a option makes the function autoloadable, equivalent to autoload -U function.

The function compdef can be used to associate existing completion functions with new commands. For example,

 
compdef _pids foo

uses the function _pids to complete process IDs for the command foo.

Note also the _gnu_generic function described below, which can be used to complete options for commands that understand the ‘--help’ option.

COMPLETION SYSTEM CONFIGURATION

This section gives a short overview of how the completion system works, and then more detail on how users can configure how and when matches are generated.

    Overview

When completion is attempted somewhere on the command line the completion system begins building the context. The context represents everything that the shell knows about the meaning of the command line and the significance of the cursor position. This takes account of a number of things including the command word (such as ‘grep’ or ‘zsh’) and options to which the current word may be an argument (such as the ‘-o’ option to zsh which takes a shell option as an argument).

The context starts out very generic ("we are beginning a completion") and becomes more specific as more is learned ("the current word is in a position that is usually a command name" or "the current word might be a variable name" and so on). Therefore the context will vary during the same call to the completion system.

This context information is condensed into a string consisting of multiple fields separated by colons, referred to simply as ‘the context’ in the remainder of the documentation. Note that a user of the completion system rarely needs to compose a context string, unless for example a new function is being written to perform completion for a new command. What a user may need to do is compose a style pattern, which is matched against a context when needed to look up context-sensitive options that configure the completion system.

The next few paragraphs explain how a context is composed within the completion function suite. Following that is discussion of how styles are defined. Styles determine such things as how the matches are generated, similarly to shell options but with much more control. They are defined with the zstyle builtin command (see zshmodules(1)).

The context string always consists of a fixed set of fields, separated by colons and with a leading colon before the first. Fields which are not yet known are left empty, but the surrounding colons appear anyway. The fields are always in the order :completion:function:completer:command:argument:tag. These have the following meaning:

o The literal string completion, saying that this style is used by the completion system. This distinguishes the context from those used by, for example, zle widgets and ZFTP functions.

o The function, if completion is called from a named widget rather than through the normal completion system. Typically this is blank, but it is set by special widgets such as predict-on and the various functions in the Widget directory of the distribution to the name of that function, often in an abbreviated form.

o The completer currently active, the name of the function without the leading underscore and with other underscores converted to hyphens. A ‘completer’ is in overall control of how completion is to be performed; ‘complete’ is the simplest, but other completers exist to perform related tasks such as correction, or to modify the behaviour of a later completer. See the section ‘Control Functions’ below for more information.

o The command or a special -context-, just at it appears following the #compdef tag or the compdef function. Completion functions for commands that have sub-commands usually modify this field to contain the name of the command followed by a minus sign and the sub-command. For example, the completion function for the cvs command sets this field to cvs-add when completing arguments to the add subcommand.

o The argument; this indicates which command line or option argument we are completing. For command arguments this generally takes the form argument-n, where n is the number of the argument, and for arguments to options the form option-opt-n where n is the number of the argument to option opt. However, this is only the case if the command line is parsed with standard UNIX-style options and arguments, so many completions do not set this.

o The tag. As described previously, tags are used to discriminate between the types of matches a completion function can generate in a certain context. Any completion function may use any tag name it likes, but a list of the more common ones is given below.

The context is gradually put together as the functions are executed, starting with the main entry point, which adds :completion: and the function element if necessary. The completer then adds the completer element. The contextual completion adds the command and argument options. Finally, the tag is added when the types of completion are known. For example, the context name

 
:completion::complete:dvips:option-o-1:files

says that normal completion was attempted as the first argument to the option -o of the command dvips:

 
dvips -o ...

and the completion function will generate filenames.
Usually completion will be tried for all possible tags in an order given by the completion function. However, this can be altered by using the tag-order style. Completion is then restricted to the list of given tags in the given order.
The _complete_help bindable command shows all the contexts and tags available for completion at a particular point. This provides an easy way of finding information for tag-order and other styles. It is described in the section ‘Bindable Commands’ below.
When looking up styles the completion system uses full context names, including the tag. Looking up the value of a style therefore consists of two things: the context, which is matched to the most specific (best fitting) style pattern, and the name of the style itself, which must be matched exactly. The following examples demonstrate that style patterns may be loosely defined for styles that apply broadly, or as tightly defined as desired for styles that apply in narrower circumstances.
For example, many completion functions can generate matches in a simple and a verbose form and use the verbose style to decide which form should be used. To make all such functions use the verbose form, put

 
zstyle ’:completion:*’ verbose yes

in a startup file (probably .zshrc). This gives the verbose style the value yes in every context inside the completion system, unless that context has a more specific definition. It is best to avoid giving the context as ‘*’ in case the style has some meaning outside the completion system.
Many such general purpose styles can be configured simply by using the compinstall function.
A more specific example of the use of the verbose style is by the completion for the kill builtin. If the style is set, the builtin lists full job texts and process command lines; otherwise it shows the bare job numbers and PIDs. To turn the style off for this use only:

 
zstyle ’:completion:*:*:kill:*:*’ verbose no

For even more control, the style can use one of the tags ‘jobs’ or ‘processes’. To turn off verbose display only for jobs:

 
zstyle ’:completion:*:*:kill:*:jobs’ verbose no

The -e option to zstyle even allows completion function code to appear as the argument to a style; this requires some understanding of the internals of completion functions (see see zshcompwid(1))). For example,

 
zstyle -e ’:completion:*’ hosts ’reply=($myhosts)’

This forces the value of the hosts style to be read from the variable myhosts each time a host name is needed; this is useful if the value of myhosts can change dynamically. For another useful example, see the example in the description of the file-list style below. This form can be slow and should be avoided for commonly examined styles such as menu and list-rows-first.

Note that the order in which styles are defined does not matter; the style mechanism uses the most specific possible match for a particular style to determine the set of values. More precisely, strings are preferred over patterns (for example, ‘:completion::complete:::foo’ is more specific than ‘:completion::complete:::*’), and longer patterns are preferred over shorter patterns.

A good rule of thumb is that any completion style pattern that needs to include more than one wildcard (*) and that does not end in a tag name, should include all six colons (:), possibly surrounding additional wildcards.

Style names like those of tags are arbitrary and depend on the completion function. However, the following two sections list some of the most common tags and styles.

    Standard Tags

Some of the following are only used when looking up particular styles and do not refer to a type of match.

accounts
  used to look up the users-hosts style
all-expansions
  used by the _expand completer when adding the single string containing all possible expansions
all-files
  for the names of all files (as distinct from a particular subset, see the globbed-files tag).
arguments
  for arguments to a command
arrays for names of array parameters
association-keys
  for keys of associative arrays; used when completing inside a subscript to a parameter of this type
bookmarks
  when completing bookmarks (e.g. for URLs and the zftp function suite)
builtins
  for names of builtin commands
characters
  for single characters in arguments of commands such as stty. Also used when completing character classes after an opening bracket
colormapids
  for X colormap ids
colors for color names
commands
  for names of external commands. Also used by complex commands such as cvs when completing names subcommands.
contexts
  for contexts in arguments to the zstyle builtin command
corrections
  used by the _approximate and _correct completers for possible corrections
cursors
  for cursor names used by X programs
default
  used in some contexts to provide a way of supplying a default when more specific tags are also valid. Note that this tag is used when only the function field of the context name is set
descriptions
  used when looking up the value of the format style to generate descriptions for types of matches
devices
  for names of device special files
directories
  for names of directories -- local-directories is used instead when completing arguments of cd and related builtin commands when the cdpath array is set
directory-stack
  for entries in the directory stack
displays
  for X display names
domains
  for network domains
expansions
  used by the _expand completer for individual words (as opposed to the complete set of expansions) resulting from the expansion of a word on the command line
extensions
  for X server extensions
file-descriptors
  for numbers of open file descriptors
files the generic file-matching tag used by functions completing filenames
fonts for X font names
fstypes
  for file system types (e.g. for the mount command)
functions
  names of functions -- normally shell functions, although certain commands may understand other kinds of function
globbed-files
  for filenames when the name has been generated by pattern matching
groups for names of user groups
history-words
  for words from the history
hosts for hostnames
indexes
  for array indexes
jobs for jobs (as listed by the ‘jobs’ builtin)
interfaces
  for network interfaces
keymaps
  for names of zsh keymaps
keysyms
  for names of X keysyms
libraries
  for names of system libraries
limits for system limits
local-directories
  for names of directories that are subdirectories of the current working directory when completing arguments of cd and related builtin commands (compare path-directories) -- when the cdpath array is unset, directories is used instead
manuals
  for names of manual pages
mailboxes
  for e-mail folders
maps for map names (e.g. NIS maps)
messages
  used to look up the format style for messages
modifiers
  for names of X modifiers
modules
  for modules (e.g. zsh modules)
my-accounts
  used to look up the users-hosts style
named-directories
  for named directories (you wouldn’t have guessed that, would you?)
names for all kinds of names
newsgroups
  for USENET groups
nicknames
  for nicknames of NIS maps
options
  for command options
original
  used by the _approximate, _correct and _expand completers when offering the original string as a match
other-accounts
  used to look up the users-hosts style
other-files
  for the names of any non-directory files. This is used instead of all-files when the list-dirs-first style is in effect.
packages
  for packages (e.g. rpm or installed Debian packages)
parameters
  for names of parameters
path-directories
  for names of directories found by searching the cdpath array when completing arguments of cd and related builtin commands (compare local-directories)
paths used to look up the values of the expand, ambiguous and special-dirs styles
pods for perl pods (documentation files)
ports for communication ports
prefixes
  for prefixes (like those of a URL)
printers
  for print queue names
processes
  for process identifiers
processes-names
  used to look up the command style when generating the names of processes for killall
sequences
  for sequences (e.g. mh sequences)
sessions
  for sessions in the zftp function suite
signals
  for signal names
strings
  for strings (e.g. the replacement strings for the cd builtin command)
styles for styles used by the zstyle builtin command
suffixes
  for filename extensions
tags for tags (e.g. rpm tags)
targets
  for makefile targets
time-zones
  for time zones (e.g. when setting the TZ parameter)
types for types of whatever (e.g. address types for the xhost command)
urls used to look up the urls and local styles when completing URLs
users for usernames
values for one of a set of values in certain lists
variant
  used by _pick_variant to look up the command to run when determining what program is installed for a particular command name.
visuals
  for X visuals
warnings
  used to look up the format style for warnings
widgets
  for zsh widget names
windows
  for IDs of X windows
zsh-options
  for shell options

    Standard Styles

Note that the values of several of these styles represent boolean values. Any of the strings ‘true’, ‘on’, ‘yes’, and ‘1’ can be used for the value ‘true’ and any of the strings ‘false’, ‘off’, ‘no’, and ‘0’ for the value ‘false’. The behavior for any other value is undefined except where explicitly mentioned. The default value may be either ‘true’ or ‘false’ if the style is not set.

Some of these styles are tested first for every possible tag corresponding to a type of match, and if no style was found, for the default tag. The most notable styles of this type are menu, list-colors and styles controlling completion listing such as list-packed and last-prompt. When tested for the default tag, only the function field of the context will be set so that a style using the default tag will normally be defined along the lines of:

zstyle ’:completion:*:default’ menu ...

accept-exact
  This is tested for the default tag in addition to the tags valid for the current context. If it is set to ‘true’ and any of the trial matches is the same as the string on the command line, this match will immediately be accepted (even if it would otherwise be considered ambiguous).

When completing pathnames (where the tag used is ‘paths’) this style accepts any number of patterns as the value in addition to the boolean values. Pathnames matching one of these patterns will be accepted immediately even if the command line contains some more partially typed pathname components and these match no file under the directory accepted.

This style is also used by the _expand completer to decide if words beginning with a tilde or parameter expansion should be expanded. For example, if there are parameters foo and foobar, the string ‘$foo’ will only be expanded if accept-exact is set to ‘true’; otherwise the completion system will be allowed to complete $foo to $foobar. If the style is set to ‘continue’, _expand will add the expansion as a match and the completion system will also be allowed to continue.

accept-exact-dirs
  This is used by filename completion. Unlike accept-exact it is a boolean. By default, filename completion examines all components of a path to see if there are completions of that component, even if the component matches an existing directory. For example, when completion after /usr/bin/, the function examines possible completions to /usr.

When this style is ‘true’, any prefix of a path that matches an existing directory is accepted without any attempt to complete it further. Hence, in the given example, the path /usr/bin/ is accepted immediately and completion tried in that directory.

If you wish to inhibit this behaviour entirely, set the path-completion style (see below) to ‘false’.

add-space
  This style is used by the _expand completer. If it is ‘true’ (the default), a space will be inserted after all words resulting from the expansion, or a slash in the case of directory names. If the value is ‘file’, the completer will only add a space to names of existing files. Either a boolean ‘true’ or the value ‘file’ may be combined with ‘subst’, in which case the completer will not add a space to words generated from the expansion of a substitution of the form ‘$(...)’ or ‘${...}’.

The _prefix completer uses this style as a simple boolean value to decide if a space should be inserted before the suffix.

ambiguous
  This applies when completing non-final components of filename paths, in other words those with a trailing slash. If it is set, the cursor is left after the first ambiguous component, even if menu completion is in use. The style is always tested with the paths tag.
assign-list
  When completing after an equals sign that is being treated as an assignment, the completion system normally completes only one filename. In some cases the value may be a list of filenames separated by colons, as with PATH and similar parameters. This style can be set to a list of patterns matching the names of such parameters.

The default is to complete lists when the word on the line already contains a colon.

auto-description
  If set, this style’s value will be used as the description for options that are not described by the completion functions, but that have exactly one argument. The sequence ‘%d’ in the value will be replaced by the description for this argument. Depending on personal preferences, it may be useful to set this style to something like ‘specify: %d’. Note that this may not work for some commands.
avoid-completer
  This is used by the _all_matches completer to decide if the string consisting of all matches should be added to the list currently being generated. Its value is a list of names of completers. If any of these is the name of the completer that generated the matches in this completion, the string will not be added.

The default value for this style is ‘_expand _old_list _correct _approximate’, i.e. it contains the completers for which a string with all matches will almost never be wanted.

cache-path
  This style defines the path where any cache files containing dumped completion data are stored. It defaults to ‘$ZDOTDIR/.zcompcache’, or ‘$HOME/.zcompcache’ if $ZDOTDIR is not defined. The completion cache will not be used unless the use-cache style is set.
cache-policy
  This style defines the function that will be used to determine whether a cache needs rebuilding. See the section on the _cache_invalid function below.
call-command
  This style is used in the function for commands such as make and ant where calling the command directly to generate matches suffers problems such as being slow or, as in the case of make can potentially cause actions in the makefile to be executed. If it is set to ‘true’ the command is called to generate matches. The default value of this style is ‘false’.
command
  In many places, completion functions need to call external commands to generate the list of completions. This style can be used to override the command that is called in some such cases. The elements of the value are joined with spaces to form a command line to execute. The value can also start with a hyphen, in which case the usual command will be added to the end; this is most useful for putting ‘builtin’ or ‘command’ in front to make sure the appropriate version of a command is called, for example to avoid calling a shell function with the same name as an external command.

As an example, the completion function for process IDs uses this style with the processes tag to generate the IDs to complete and the list of processes to display (if the verbose style is ‘true’). The list produced by the command should look like the output of the ps command. The first line is not displayed, but is searched for the string ‘PID’ (or ‘pid’) to find the position of the process IDs in the following lines. If the line does not contain ‘PID’, the first numbers in each of the other lines are taken as the process IDs to complete.

Note that the completion function generally has to call the specified command for each attempt to generate the completion list. Hence care should be taken to specify only commands that take a short time to run, and in particular to avoid any that may never terminate.

command-path
  This is a list of directories to search for commands to complete. The default for this style is the value of the special parameter path.
commands
  This is used by the function completing sub-commands for the system initialisation scripts (residing in /etc/init.d or somewhere not too far away from that). Its values give the default commands to complete for those commands for which the completion function isn’t able to find them out automatically. The default for this style are the two strings ‘start’ and ‘stop’.
complete
  This is used by the _expand_alias function when invoked as a bindable command. If set to ‘true’ and the word on the command line is not the name of an alias, matching alias names will be completed.
complete-options
  This is used by the completer for cd, chdir and pushd. For these commands a - is used to introduce a directory stack entry and completion of these is far more common than completing options. Hence unless the value of this style is ‘true’ options will not be completed, even after an initial -. If it is ‘true’, options will be completed after an initial - unless there is a preceding -- on the command line.
completer
  The strings given as the value of this style provide the names of the completer functions to use. The available completer functions are described in the section ‘Control Functions’ below.

Each string may be either the name of a completer function or a string of the form ‘function:name’. In the first case the completer field of the context will contain the name of the completer without the leading underscore and with all other underscores replaced by hyphens. In the second case the function is the name of the completer to call, but the context will contain the user-defined name in the completer field of the context. If the name starts with a hyphen, the string for the context will be build from the name of the completer function as in the first case with the name appended to it. For example:

 
zstyle ’:completion:*’ completer _complete _complete:-foo

Here, completion will call the _complete completer twice, once using ‘complete’ and once using ‘complete-foo’ in the completer field of the context. Normally, using the same completer more than once only makes sense when used with the ‘functions:name’ form, because otherwise the context name will be the same in all calls to the completer; possible exceptions to this rule are the _ignored and _prefix completers.

The default value for this style is ‘_complete _ignored’: only completion will be done, first using the ignored-patterns style and the $fignore array and then without ignoring matches.

condition
  This style is used by the _list completer function to decide if insertion of matches should be delayed unconditionally. The default is ‘true’.
delimiters
  This style is used when adding a delimiter for use with history modifiers or glob qualifiers that have delimited arguments. It is an array of preferred delimiters to add. Non-special characters are preferred as the completion system may otherwise become confused. The default list is :, +, /, -, %. The list may be empty to force a delimiter to be typed.
disabled
  If this is set to ‘true’, the _expand_alias completer and bindable command will try to expand disabled aliases, too. The default is ‘false’.
domains
  A list of names of network domains for completion. If this is not set, domain names will be taken from the file /etc/resolv.conf.
environ
  The environ style is used when completing for ‘sudo’. It is set to an array of ‘VAR=value’ assignments to be exported into the local environment before the completion for the target command is invoked.
zstyle ’:completion:*:sudo::’ environ \
  PATH="/sbin:/usr/sbin:$PATH" HOME="/root"

expand This style is used when completing strings consisting of multiple parts, such as path names.

If one of its values is the string ‘prefix’, the partially typed word from the line will be expanded as far as possible even if trailing parts cannot be completed.

If one of its values is the string ‘suffix’, matching names for components after the first ambiguous one will also be added. This means that the resulting string is the longest unambiguous string possible. However, menu completion can be used to cycle through all matches.

fake This style may be set for any completion context. It specifies additional strings that will always be completed in that context. The form of each string is ‘value:description’; the colon and description may be omitted, but any literal colons in value must be quoted with a backslash. Any description provided is shown alongside the value in completion listings.

It is important to use a sufficiently restrictive context when specifying fake strings. Note that the styles fake-files and fake-parameters provide additional features when completing files or parameters.

fake-always
  This works identically to the fake style except that the ignored-patterns style is not applied to it. This makes it possible to override a set of matches completely by setting the ignored patterns to ‘*’.

The following shows a way of supplementing any tag with arbitrary data, but having it behave for display purposes like a separate tag. In this example we use the features of the tag-order style to divide the named-directories tag into two when performing completion with the standard completer complete for arguments of cd. The tag named-directories-normal behaves as normal, but the tag named-directories-mine contains a fixed set of directories. This has the effect of adding the match group ‘extra directories’ with the given completions.

 
zstyle ’:completion::complete:cd:*’ tag-order \
  ’named-directories:-mine:extra\ directories
  named-directories:-normal:named\ directories *’
zstyle ’:completion::complete:cd:*:named-directories-mine’ \
  fake-always mydir1 mydir2
zstyle ’:completion::complete:cd:*:named-directories-mine’ \
  ignored-patterns ’*’

fake-files
  This style is used when completing files and looked up without a tag. Its values are of the form ‘dir:names...’. This will add the names (strings separated by spaces) as possible matches when completing in the directory dir, even if no such files really exist. The dir may be a pattern; pattern characters or colons in dir should be quoted with a backslash to be treated literally.

This can be useful on systems that support special file systems whose top-level pathnames can not be listed or generated with glob patterns. It can also be used for directories for which one does not have read permission.

The pattern form can be used to add a certain ‘magic’ entry to all directories on a particular file system.

fake-parameters
  This is used by the completion function for parameter names. Its values are names of parameters that might not yet be set but should be completed nonetheless. Each name may also be followed by a colon and a string specifying the type of the parameter (like ‘scalar’, ‘array’ or ‘integer’). If the type is given, the name will only be completed if parameters of that type are required in the particular context. Names for which no type is specified will always be completed.
file-list
  This style controls whether files completed using the standard builtin mechanism are to be listed with a long list similar to ls -l. Note that this feature uses the shell module zsh/stat for file information; this loads the builtin stat which will replace any external stat executable. To avoid this the following code can be included in an initialization file:

 
zmodload -i zsh/stat
disable stat

The style may either be set to a ‘true’ value (or ‘all’), or one of the values ‘insert’ or ‘list’, indicating that files are to be listed in long format in all circumstances, or when attempting to insert a file name, or when listing file names without attempting to insert one.

More generally, the value may be an array of any of the above values, optionally followed by =num. If num is present it gives the maximum number of matches for which long listing style will be used. For example,

 
zstyle ’:completion:*’ file-list list=20 insert=10

specifies that long format will be used when listing up to 20 files or inserting a file with up to 10 matches (assuming a listing is to be shown at all, for example on an ambiguous completion), else short format will be used.

 
zstyle -e ’:completion:*’ file-list \
       ’(( ${+NUMERIC} )) && reply=(true)’

specifies that long format will be used any time a numeric argument is supplied, else short format.

file-patterns
  This is used by the standard function for completing filenames, _files. If the style is unset up to three tags are offered, ‘globbed-files’,‘directories’ and ‘all-files’, depending on the types of files expected by the caller of _files. The first two (‘globbed-files’ and ‘directories’) are normally offered together to make it easier to complete files in sub-directories.

The file-patterns style provides alternatives to the default tags, which are not used. Its value consists of elements of the form ‘pattern:tag’; each string may contain any number of such specifications separated by spaces.

The pattern is a pattern that is to be used to generate filenames. Any occurrence of the sequence ‘%p’ is replaced by any pattern(s) passed by the function calling _files. Colons in the pattern must be preceded by a backslash to make them distinguishable from the colon before the tag. If more than one pattern is needed, the patterns can be given inside braces, separated by commas.

The tags of all strings in the value will be offered by _files and used when looking up other styles. Any tags in the same word will be offered at the same time and before later words. If no ‘:tag’ is given the ‘files’ tag will be used.

The tag may also be followed by an optional second colon and a description, which will be used for the ‘%d’ in the value of the format style (if that is set) instead of the default description supplied by the completion function. If the description given here contains itself a ‘%d’, that is replaced with the description supplied by the completion function.

For example, to make the rm command first complete only names of object files and then the names of all files if there is no matching object file:

 
zstyle ’:completion:*:*:rm:*:*’ file-patterns \
    ’*.o:object-files’ ’%p:all-files’

To alter the default behaviour of file completion -- offer files matching a pattern and directories on the first attempt, then all files -- to offer only matching files on the first attempt, then directories, and finally all files:

 
zstyle ’:completion:*’ file-patterns \
    ’%p:globbed-files’ ’*(-/):directories’ ’*:all-files’

This works even where there is no special pattern: _files matches all files using the pattern ‘*’ at the first step and stops when it sees this pattern. Note also it will never try a pattern more than once for a single completion attempt.

During the execution of completion functions, the EXTENDED_GLOB option is in effect, so the characters ‘#’, ‘~’ and ‘^’ have special meanings in the patterns.

file-sort
  The standard filename completion function uses this style without a tag to determine in which order the names should be listed; menu completion will cycle through them in the same order. The possible values are: ‘size’ to sort by the size of the file; ‘links’ to sort by the number of links to the file; ‘modification’ (or ‘time’ or ‘date’) to sort by the last modification time; ‘access’ to sort by the last access time; and ‘inode’ (or ‘change’) to sort by the last inode change time. If the style is set to any other value, or is unset, files will be sorted alphabetically by name. If the value contains the string ‘reverse’, sorting is done in the opposite order. If the value contains the string ‘follow’, timestamps are associated with the targets of symbolic links; the default is to use the timestamps of the links themselves.
filter This is used by the LDAP plugin for e-mail address completion to specify the attributes to match against when filtering entries. So for example, if the style is set to ‘sn’, matching is done against surnames. Standard LDAP filtering is used so normal completion matching is bypassed. If this style is not set, the LDAP plugin is skipped. You may also need to set the command style to specify how to connect to your LDAP server.
force-list
  This forces a list of completions to be shown at any point where listing is done, even in cases where the list would usually be suppressed. For example, normally the list is only shown if there are at least two different matches. By setting this style to ‘always’, the list will always be shown, even if there is only a single match that will immediately be accepted. The style may also be set to a number. In this case the list will be shown if there are at least that many matches, even if they would all insert the same string.

This style is tested for the default tag as well as for each tag valid for the current completion. Hence the listing can be forced only for certain types of match.

format If this is set for the descriptions tag, its value is used as a string to display above matches in completion lists. The sequence ‘%d’ in this string will be replaced with a short description of what these matches are. This string may also contain the following sequences to specify output attributes as described in the section EXPANSION OF PROMPT SEQUENCES in zshmisc(1): ‘%B’, ‘%S’, ‘%U’, ‘%F’, ‘%K’ and their lower case counterparts, as well as ‘%{...%}’. ‘%F’, ‘%K’ and ‘%{...%}’ take arguments in the same form as prompt expansion. Note that the sequence ‘%G’ is not available; an argument to ‘%{’ should be used instead.

The style is tested with each tag valid for the current completion before it is tested for the descriptions tag. Hence different format strings can be defined for different types of match.

Note also that some completer functions define additional ‘%’-sequences. These are described for the completer functions that make use of them.

Some completion functions display messages that may be customised by setting this style for the messages tag. Here, the ‘%d’ is replaced with a message given by the completion function.

Finally, the format string is looked up with the warnings tag, for use when no matches could be generated at all. In this case the ‘%d’ is replaced with the descriptions for the matches that were expected separated by spaces. The sequence ‘%D’ is replaced with the same descriptions separated by newlines.

It is possible to use printf-style field width specifiers with ‘%d’ and similar escape sequences. This is handled by the zformat builtin command from the zsh/zutil module, see zshmodules(1).

glob This is used by the _expand completer. If it is set to ‘true’ (the default), globbing will be attempted on the words resulting from a previous substitution (see the substitute style) or else the original string from the line.
global If this is set to ‘true’ (the default), the _expand_alias completer and bindable command will try to expand global aliases.
group-name
  The completion system can group different types of matches, which appear in separate lists. This style can be used to give the names of groups for particular tags. For example, in command position the completion system generates names of builtin and external commands, names of aliases, shell functions and parameters and reserved words as possible completions. To have the external commands and shell functions listed separately:

 
zstyle ’:completion:*:*:-command-:*:commands’ \
       group-name commands
zstyle ’:completion:*:*:-command-:*:functions’ \
       group-name functions

As a consequence, any match with the same tag will be displayed in the same group.

If the name given is the empty string the name of the tag for the matches will be used as the name of the group. So, to have all different types of matches displayed separately, one can just set:

 
zstyle ’:completion:*’ group-name ’’

All matches for which no group name is defined will be put in a group named -default-.

group-order
  This style is additional to the group-name style to specify the order for display of the groups defined by that style (compare tag-order, which determines which completions appear at all). The groups named are shown in the given order; any other groups are shown in the order defined by the completion function.

For example, to have names of builtin commands, shell functions and external commands appear in that order when completing in command position:

 
zstyle ’:completion:*:*:-command-:*:*’ group-order \
       builtins functions commands

groups A list of names of UNIX groups. If this is not set, group names are taken from the YP database or the file ‘/etc/group’.
hidden If this is set to ‘true’, matches for the given context will not be listed, although any description for the matches set with the format style will be shown. If it is set to ‘all’, not even the description will be displayed.

Note that the matches will still be completed; they are just not shown in the list. To avoid having matches considered as possible completions at all, the tag-order style can be modified as described below.

hosts A list of names of hosts that should be completed. If this is not set, hostnames are taken from the file ‘/etc/hosts’.
hosts-ports
  This style is used by commands that need or accept hostnames and network ports. The strings in the value should be of the form ‘host:port’. Valid ports are determined by the presence of hostnames; multiple ports for the same host may appear.
ignore-line
  This is tested for each tag valid for the current completion. If it is set to ‘true’, none of the words that are already on the line will be considered as possible completions. If it is set to ‘current’, the word the cursor is on will not be considered as a possible completion. The value ‘current-shown’ is similar but only applies if the list of completions is currently shown on the screen. Finally, if the style is set to ‘other’, all words on the line except for the current one will be excluded from the possible completions.

The values ‘current’ and ‘current-shown’ are a bit like the opposite of the accept-exact style: only strings with missing characters will be completed.

Note that you almost certainly don’t want to set this to ‘true’ or ‘other’ for a general context such as ‘:completion:*’. This is because it would disallow completion of, for example, options multiple times even if the command in question accepts the option more than once.

ignore-parents
  The style is tested without a tag by the function completing pathnames in order to determine whether to ignore the names of directories already mentioned in the current word, or the name of the current working directory. The value must include one or both of the following strings:

parent The name of any directory whose path is already contained in the word on the line is ignored. For example, when completing after foo/../, the directory foo will not be considered a valid completion.
pwd The name of the current working directory will not be completed; hence, for example, completion after ../ will not use the name of the current directory.
In addition, the value may include one or both of:
.. Ignore the specified directories only when the word on the line contains the substring ‘../’.
directory
  Ignore the specified directories only when names of directories are completed, not when completing names of files.
Excluded values act in a similar fashion to values of the ignored-patterns style, so they can be restored to consideration by the _ignored completer.

extra-verbose
  If set, the completion listing is more verbose at the cost of a probable decrease in completion speed. Completion performance will suffer if this style is set to ‘true’.
ignored-patterns
  A list of patterns; any trial completion matching one of the patterns will be excluded from consideration. The _ignored completer can appear in the list of completers to restore the ignored matches. This is a more configurable version of the shell parameter $fignore.

Note that the EXTENDED_GLOB option is set during the execution of completion functions, so the characters ‘#’, ‘~’ and ‘^’ have special meanings in the patterns.

insert This style is used by the _all_matches completer to decide whether to insert the list of all matches unconditionally instead of adding the list as another match.
insert-ids