NAME

zshall - the Z shell meta-man page

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. It does not provide compatibility with POSIX or other shells in its default operating mode: see the section Compatibility below. 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 HTTP and anonymous FTP site.

ftp://ftp.zsh.org/pub/
https://www.zsh.org/pub/

) The up-to-date source code is available via Git from Sourceforge. See https://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 https://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 https://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.

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). The long option ` --emulate' followed (in a separate word) by an emulation mode may be passed to the shell. The emulation modes are those described for the emulate builtin, see zshbuiltins(1). The ` - -emulate' option must precede any other options (which might otherwise be overridden), but following options are honoured, so may be used to modify the requested emulation mode. Note that certain extra steps are taken to ensure a smooth emulation when this option is used compared with the emulate command within the shell: for example, variables that conflict with POSIX usage such as path are not defined within the shell. 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, 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:

•

changing directories with the cd builtin

•

changing or unsetting the EGID, EUID, GID, HISTFILE, HISTSIZE, IFS, LD_AOUT_LIBRARY_PATH, LD_AOUT_PRELOAD, LD_LIBRARY_PATH, LD_PRELOAD, MODULE_PATH, module_path, PATH, path, SHELL, UID and USERNAME parameters

•

specifying command names containing /

•

specifying command pathnames using hash

•

redirecting output to files

•

using the exec builtin command to replace the shell with another command

•

using jobs -Z to overwrite the shell process' argument and environment space

•

using the ARGV0 parameter to override argv[0] for external commands

•

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

|

for matching either of two alternatives

~, ^

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, 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, 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, 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.

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.

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.

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'.

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'.

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'.

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 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.

function word ... [ () ] [ term ] sublist

This is a short form of function.

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:

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Failure to parse shell options passed when invoking the shell

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Failure to change options with the set builtin

•

Parse errors of all sorts, including failures to parse mathematical expressions

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Failures to set or modify variable behaviour with typeset, local, declare, export, integer, float

•

Execution of incorrectly positioned loop control structures ( continue, break)

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Attempts to use regular expression with no regular expression module available

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Disallowed operations when the RESTRICTED options is set

•

Failure to create a pipe needed for a pipeline

•

Failure to create a multio

•

Failure to autoload a module needed for a declared shell feature

•

Errors creating command or process substitutions

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Syntax errors in glob qualifiers

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File generation errors where not caught by the option BAD_PATTERN

•

All bad patterns used for matching within case statements

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File generation failures where not caused by NO_MATCH or similar options

•

All file generation errors where the pattern was used to create a multio

•

Memory errors where detected by the shell

•

Invalid subscripts to shell variables

•

Attempts to assign read-only variables

•

Logical errors with variables such as assignment to the wrong type

•

Use of invalid variable names

•

Errors in variable substitution syntax

•

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:

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Any plain string or glob pattern

•

Any quoted string, using any quoting method (note that the quotes must be part of the alias definition for this to be eligible)

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Any parameter reference or command substitution

•

Any series of the foregoing, concatenated without whitespace or other tokens between them

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Any reserved word (case, do, else, etc.)

•

With global aliasing, any command separator, any redirection operator, and ` (' or `)' when not part of a glob pattern

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. 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. 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.

Alias difficulties

Although aliases can be used in ways that bend normal shell syntax, not every string of non-white-space characters can be used as an alias. Any set of characters not listed as a word above is not a word, hence no attempt is made to expand it as an alias, no matter how it is defined (i.e. via the builtin or the special parameter aliases described in the section THE ZSH/PARAMETER MODULE in zshmodules(1)). However, as noted in the case of POSIX_ALIASES above, the shell does not attempt to deduce whether the string corresponds to a word at the time the alias is created. For example, an expression containing an = at the start of a command line is an assignment and cannot be expanded as an alias; a lone = is not an assignment but can only be set as an alias using the parameter, as otherwise the = is taken part of the syntax of the builtin command. 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. 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. There is a commonly encountered problem with aliases illustrated by the following code: 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: Because aliases are expanded in function definitions, this causes the following command to be executed: 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, 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 the first character of $histchars (default ` !').

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.

<<< 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: 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: 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 >&$param if param is readonly. If the option CLOBBER is unset, it is an error to open a file descriptor using a parameter that is already set to an open file descriptor previously allocated by this mechanism. Unsetting the parameter before using it for allocating a file descriptor avoids the error. Note that this mechanism merely allocates or closes a file descriptor; it does not perform any redirections from or to it. It is usually convenient to allocate a file descriptor prior to use as an argument to exec. The syntax does not in any case work when used around complex commands such as parenthesised subshells or loops, where the opening brace is interpreted as part of a command list to be executed in the current shell. The following shows a typical sequence of allocation, use, and closing of a file descriptor: Note that the expansion of the variable in the expression >&$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: writes the date to two files, named ` foo' and `bar'. Note that a pipe is an implicit redirection; thus writes the date to the file ` foo', and also pipes it to cat. Note also that redirections are always expanded in order. This happens regardless of the setting of the MULTIOS option, but with the option in effect there are additional consequences. For example, the meaning of the expression >&1 will change after a previous redirection: In the case above, the >&1 refers to the standard output at the start of the line; the result is similar to the tee command. However, consider: As redirections are evaluated in order, when the >&1 is encountered the standard output is set to the file output and another copy of the output is therefore sent to that file. This is unlikely to be what is intended. 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 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 or even 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 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 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: 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: 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 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 return status of the function becomes the status of the command. If the function wishes to mimic the behaviour of the shell when the command is not found, it should print the message ` command not found: cmd' to standard error and return 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: 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.

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 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: and In fact, the functions command outputs `builtin autoload -X' as the body of an autoloaded function. This is done so that 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:

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, outputs the following: 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).

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.

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 ('function traps') and ('list traps') are equivalent in most ways, the exceptions being the following:

•

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.

•

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.

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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: 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. One additional side effect is that use of disown with a job created by suspending shell code in this fashion is delayed: the job can only be disowned once any process started from the parent shell has terminated. At that point, the disowned job disappears silently from the job list. 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

The last job whose command line begins with string.

%?string

The last 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 is equivalent to 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: 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: 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, 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, 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 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.

-v varname

true if shell variable varname is 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 two forms are exactly equivalent. The ` =' form is the traditional shell syntax (and hence the only one generally used with the test and [ builtins); the ` ==' form provides compatibility with other sorts of computer language.

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.

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, 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: 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:

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.

%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.

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.

%<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.

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 left-to-right fashion. On each argument, any of the five steps that are needed are performed one after the other. Hence, for example, all the parts of parameter expansion are completed before command substitution is started. 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, including inside double quotes (but not inside single quotes '...' or C-style quotes $'...' nor when escaped with a backslash). The first character is followed by an optional event designator (see the section `Event Designators') and then an optional word designator (the section `Word Designators'); if neither of these designators is present, no history expansion occurs. Input lines containing history expansions are echoed after being expanded, but before any other expansions take place and before the command is executed. It is this expanded form that is recorded as the history event for later references. History expansions do not nest. By default, a history reference with no event designator refers to the same event as any preceding history reference on that command line; if it is the only history reference in a command, it refers to the previous command. However, if the option CSH_JUNKIE_HISTORY is set, then every history reference with no event specification always refers to the previous command. For example, ` !' is the event designator for the previous command, so ` !!:1' always refers to the first word of the previous command, and ` !!$' 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; remove ` .' path segments; and remove `..' path segments and the segments that immediately precede them.

A

Turn a file name into an absolute path as the `a' modifier does, and then pass the result through the realpath(3) library function to resolve symbolic links.

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.

P

Turn a file name into an absolute path, like realpath(3). The resulting path will be absolute, have neither ` .' nor `..' components, and refer to the same directory entry as the input filename.

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.

&

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: 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, 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: 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: (note that no MULTIOS are involved), process will be run asynchronously as far as the parent shell is concerned. The workaround is: 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, 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: outputs something resembling the following 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. In the following descriptions, `word' refers to a single word substituted on the command line, not necessarily a space delimited word. With default options, after the assignments: then $array substitutes two words, `first word' and `second word', and $scalar substitutes a single word `only word'. This may be modified by explicit or implicit word-splitting, however. The full rules are complicated and are noted at the end.

${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.

${+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,

${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.

${name/pattern/repl}

${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, and the third form replaces only if pattern matches the entire string. Both pattern and repl are subject to double-quoted substitution, so that expressions like ${name/$opat/$npat} will work, but obey 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}.

${#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.

${^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.

${=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.

${~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.

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.

%

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

Convert the substitution into an array expression, even if it otherwise would be scalar. This has lower precedence than subscripting, so one level of nested expansion is required in order that subscripts apply to array elements. Thus ${${(A)name}[1]} yields the full value of name when name is scalar.

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.

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 single word shell expansions, namely 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. With the KSH_ARRAYS option a subscript ` [*]' or `[@]' is needed to operate on the whole array, as usual.

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.

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.

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:

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)

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.

~

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: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.

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.

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.

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.

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.

B

Include the index of the beginning of the match in the result.

E

Include the index one character past the end of the match in the result (note this is inconsistent with other uses of parameter index).

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.

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.

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.

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.

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.

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.

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 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.

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):

[^...]

[!...]

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.

(...)

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.

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. The alternatives are tried in order from left to right.

^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.

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; (#c N,) 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.

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.

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: or 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: is equivalent to

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 ` ='.

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).

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.

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.

^

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.

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.

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.

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: lists all directories and symbolic links that point to directories, and lists all broken symbolic links, and lists all world-writable device files in the current directory, and lists all files in the current directory that are world-writable or world-executable, and outputs the basename of all root-owned files beginning with the string ` foo' in /tmp, ignoring symlinks, and 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. 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: 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: 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. In the third form, key is an expression that will be evaluated in arithmetic context (in its simplest form, an integer) that gives the index of the element to be assigned with value. In this form any elements not explicitly mentioned that come before the largest index to which a value is assigned are assigned an empty string. The indices may be in any order. Note that this syntax is strict: [ and ]= must not be quoted, and key may not consist of the unquoted string ]=, but is otherwise treated as a simple string. The enhanced forms of subscript expression that may be used when directly subscripting a variable name, described in the section Array Subscripts below, are not available. The syntaxes with and without the explicit key may be mixed. An implicit key is deduced by incrementing the index from the previously assigned element. Note that it is not treated as an error if latter assignments in this form overwrite earlier assignments. For example, assuming the option KSH_ARRAYS is not set, the following: causes the array variable array to contain four elements one, an empty string, three and four, in that order. In the forms where only value is specified, full command line expansion is performed. In the [key]=value form, both key and value undergo all forms of expansion allowed for single word shell expansions (this does not include filename generation); these are as performed by the parameter expansion flag (e) as described in zshparam(1). Nested parentheses may surround value and are included as part of the value, which is joined into a plain string; this differs from ksh which allows the values themselves to be arrays. A future version of zsh may support that. To cause the brackets to be interpreted as a character class for filename generation, and therefore to treat the resulting list of files as a set of values, quote the equal sign using any form of quoting. Example: To append to an array without changing the existing values, use one of the following: In the second form key may specify an existing index as well as an index off the end of the old array; any existing value is overwritten by value. Also, it is possible to use [key]+=value to append to the existing value at that index. 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: Associative arrays must be declared before assignment, by using: When name refers to an associative array, the list in an assignment is interpreted as alternating keys and values: Note that only one of the two syntaxes above may be used in any given assignment; the forms may not be mixed. This is unlike the case of numerically indexed arrays. 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: 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. In the second form it is also possible to use [key]+=value to append to the existing value at that key. Expansion is performed identically to the corresponding forms for normal arrays, as described above. To create an empty array (including associative arrays), use one of:

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, 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: 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: 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:

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. When combined with the i or I flag, the effect is to produce the index of the first character of the first/last word which matches the given pattern; note that a failed match in this case always yields 0.

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.

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.

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.

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: 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: 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: 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: 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)'

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)'

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.

FUNCNEST <S>

Integer. If greater than or equal to zero, the maximum nesting depth of shell functions. When it is exceeded, an error is raised at the point where a function is called. The default value is determined when the shell is configured, but is typically 500. Increasing the value increases the danger of a runaway function recursion causing the shell to crash. Setting a negative value turns off the check.

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)'

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.

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.

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.

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)'

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.

ZSH_ARGZERO

If zsh was invoked to run a script, this is the name of the script. Otherwise, it is the name used to invoke the current shell. This is the same as the value of $0 when the POSIX_ARGZERO option is set, but is always available.

ZSH_EXECUTION_STRING

If the shell was started with the option -c, this contains the argument passed to the option. Otherwise it is not set.

ZSH_NAME

Expands to the basename of the command used to invoke this instance of zsh.

ZSH_PATCHLEVEL

The output of `git describe --tags --long' for the zsh repository used to build the shell. 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_SCRIPT

If zsh was invoked to run a script, this is the name of the script, otherwise it is unset.

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.

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 the shell is interactive and 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 ` #').

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.

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.

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.

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.

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.

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.

REPORTMEMORY

If nonnegative, commands whose maximum resident set size (roughly speaking, main memory usage) in kilobytes is greater than this value have timing statistics reported. The format used to output statistics is the value of the TIMEFMT parameter, which is the same as for the REPORTTIME variable and the time builtin; note that by default this does not output memory usage. Appending " max RSS %M" to the value of TIMEFMT causes it to output the value that triggered the report. If REPORTTIME is also in use, at most a single report is printed for both triggers. This feature requires the getrusage() system call, commonly supported by modern Unix-like systems.

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.

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 your terminfo database, 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.

TERMINFO_DIRS <S>

A colon-seprarated list of terminfo databases, used by the `terminfo' library when the system has it; see terminfo(5). This variable is only used by certain terminal libraries, in particular ncurses; see terminfo(5) to check support on your system. If set, this causes the shell to reinitialise the terminal, making the workaround ` TERM=$TERM' unnecessary. Note that unlike other colon-separated arrays this is not tied to a zsh array.

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:

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'.

TMPSUFFIX

A filename suffix which the shell will use for temporary files created by process substitutions (e.g., ` =(list)'). Note that the value should include a leading dot ` .' if intended to be interpreted as a file extension. The default is not to append any suffix, thus this parameter should be assigned only when needed and then unset again.

watch <S> <Z> (WATCH <S>)

An array (colon-separated list) of login/logout events to report.

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:

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.

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_SPACE_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.

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.

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.

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.

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.

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)

If the string on the command line exactly matches one of the possible completions, it is accepted, even if there is another completion (i.e. that string with something else added) that also matches.

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.

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.

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.

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

If set, regular expression matching with the =~ operator will use Perl-Compatible Regular Expressions from the PCRE library. (The zsh/pcre module must be 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.

WARN_NESTED_VAR

Print a warning message when an existing parameter from an enclosing function scope, or global, is set in a function by an assignment or in math context. Assignment to shell special parameters does not cause a warning. This is the companion to WARN_CREATE_GLOBAL as in this case the warning is only printed when a parameter is not created. Where possible, use of typeset -g to set the parameter suppresses the error, but note that this needs to be used every time the parameter is set. To restrict the effect of this option to a single function scope, use ` functions -W'.

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:

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.

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 option 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.

SHARE_HISTORY <K>

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.

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.

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.

CORRECT_ALL (-O)

Try to correct the spelling of all arguments in a line.

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.

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.

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.

CHECK_RUNNING_JOBS <Z>

Check for both running and suspended jobs when CHECK_JOBS is enabled. When this option is disabled, zsh checks only for suspended jobs, which matches the default behavior of bash.

HUP <Z>

Send the HUP signal to running jobs when the shell exits.

LONG_LIST_JOBS (-R)

Print job notifications 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.

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).

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

ALIAS_FUNC_DEF <S>

By default, zsh does not allow the definition of functions using the ` name ()' syntax if name was expanded as an alias: this causes an error. This is usually the desired behaviour, as otherwise the combination of an alias and a function based on the same definition can easily cause problems.

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.

ERR_RETURN

If a command has a non-zero exit status, return immediately from the enclosing function. The logic is similar 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,

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.

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.

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]') or to apply modifiers to any parameter (` ${PWD:h}' rather than `$PWD:h').

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.

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.

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).

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:

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.

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).

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.

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.

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.

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.

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.

: [ 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.

autoload [ {+|-}RTUXdkmrtWz ] [ -w ] [ name ... ]

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.

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.

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.

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.

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.

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.

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:

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.

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.

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 command rather than forking. If command is a shell builtin command or a shell function, the shell executes it, and exits when the command is complete.

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.

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.

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 [ {+|-}UkmtTuWz ] [ -x num ] [ name ... ]

functions -M [-s] mathfn [ min [ max [ shellfn ] ] ]

functions -M [ -m pattern ... ]

functions +M [ -m ] mathfn ...

Equivalent to typeset -f, with the exception of the -x, -M and -W options. For functions -u and functions -U, see autoload, which provides additional options.

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.

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.

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.

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.

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.

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.

print [ -abcDilmnNoOpPrsSz ] [ -u n ] [ -f format ] [ -C cols ]

[ -v name ] [ -xX tabstop ] [ -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 `\M x') 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.

printf [ -v name ] 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.

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.

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.

readonly

Same as typeset -r. With the POSIX_BUILTINS option set, same as typeset -gr.

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.

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.

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.

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.

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.

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).

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.

type [ -wfpamsS ] name ...

Equivalent to whence -v.

typeset [ {+|-}AHUaghlmrtux ] [ {+|-} EFLRZip [ n ] ]

[ + ] [ name[=value] ... ]

typeset -T [ {+|-}Uglrux ] [ {+|-}LRZp [ n ] ]

[ + | SCALAR[=value] array[=( value ...)] [ sep ] ]

typeset -f [ {+|-}TUkmtuz ] [ + ] [ name ... ]

Set or display attributes and values for shell parameters.

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.

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.

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.

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.

whence [ -vcwfpamsS ] [ -x num ] name ...

For each name, indicate how it would be interpreted if used as a command name.

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.

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 ] [ -s ] [ ... ]

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.

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: 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:

vared [ -Aacghe ] [ -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. The -g flag may be given to suppress warnings from the WARN_CREATE_GLOBAL and WARN_NESTED_VAR options.

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.

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 redirected from /dev/null 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:

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:

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.

ISEARCHMATCH_ACTIVE (integer)

ISEARCHMATCH_START (integer)

ISEARCHMATCH_END (integer)

ISEARCHMATCH_ACTIVE indicates whether a part of the BUFFER is currently matched by an incremental search pattern. ISEARCHMATCH_START and ISEARCHMATCH_END give the location of the matched part and are in the same units as CURSOR. They are only valid for reading when ISEARCHMATCH_ACTIVE is non-zero.

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.

KEYS_QUEUED_COUNT (integer)

The number of bytes pushed back to the input queue and therefore available for reading immediately before any I/O is done; read-only. See also PENDING; the two values are distinct.

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.

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 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. See also KEYS_QUEUED_COUNT; the two values are distinct.

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.

registers (associative array)

The contents of each of the vi register buffers. These are typically set using vi-set-buffer followed by a delete, change or yank command.

SUFFIX_ACTIVE (integer)

SUFFIX_START (integer)

SUFFIX_END (integer)

SUFFIX_ACTIVE indicates whether an auto-removable completion suffix is currently active. SUFFIX_START and SUFFIX_END give the location of the suffix and are in the same units as CURSOR. They are only valid for reading when SUFFIX_ACTIVE is non-zero.

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.

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.

ZLE_RECURSIVE (integer)

Usually zero, but incremented inside any instance of recursive-edit. Hence indicates the current recursion level.

ZLE_STATE (scalar)

Contains a set of space-separated words that describe the current zle state.

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-line-pre-redraw

Executed whenever the input line is about to be redrawn, providing an opportunity to update the region_highlight array.

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-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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

vi-down-case (unbound) (gu) (unbound)

Read a movement command from the keyboard, and convert all characters from the cursor position to the endpoint of the movement to lowercase. If the movement command is vi-down-case, swap the case of all characters on the current line.

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.

vi-up-case (unbound) (gU) (unbound)

Read a movement command from the keyboard, and convert all characters from the cursor position to the endpoint of the movement to lowercase. If the movement command is vi-up-case, swap the case of all characters on the current line.

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.

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.

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.

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.

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.

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.

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. Aliasing this widget with ` zle -A' or replacing it with `zle -N' has no effect when interpreting key bindings, but ` zle execute-named-cmd' will invoke such an alias or replacement.

execute-last-named-cmd (ESC-z) (unbound) (unbound)

Redo the last function executed with execute-named-cmd.

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.

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).

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.

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.

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 currently selected text. In emacs terminology, this is referred to as the region and is bounded by the cursor (point) and the mark. The region is only highlighted if it is active, which is the case after the mark is modified with set-mark-command or exchange-point-and-mark. Note that whether or not the region is active has no effect on its use within emacs style widgets, it simply determines whether it is highlighted. In vi mode, the region corresponds to selected text in visual mode.

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.

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.

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.

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 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, 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_SPACE_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:

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:

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 ... ]

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.

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.

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.

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.

x:

This form is used to mark the end of matching specifications: subsequent specifications are ignored. In a single standalone list of specifications this has no use but where matching specifications are accumulated, such as from nested function calls, it can allow one function to override another.

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: 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: This makes lower case letters match their upper case counterparts. To make upper case letters match the lower case forms as well: 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: 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 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: 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: 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: Then the widget can be bound to a key using the bindkey builtin command: 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.: 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

•

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';

•

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:

•

those beginning `comp' are to be called directly; there are only a few of these;

•

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.

#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.

#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,

#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: completes files matching ` *.log' after `2> <TAB>' for any command with no more specific handler defined. Also: 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 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.

The function compdef can be used to associate existing completion functions with new commands. For example, 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:

•

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.

•

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.

•

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.

•

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.

•

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.

•

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 says that normal completion was attempted as the first argument to the option -o of the command dvips: 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 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: For even more control, the style can use one of the tags ` jobs' or ` processes'. To turn off verbose display only for jobs: 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, 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

email-plugin

for email addresses from the `_email-plugin' backend of _email_addresses

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:

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).

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.

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 ` $( ...)' or `${...}'.

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.

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.

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.

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.

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.

expand

This style is used when completing strings consisting of multiple parts, such as path names.

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.

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 ` *'.

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.

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:

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.

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

The ldap plugin of email address completion (see _email_addresses) uses this style 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.

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.

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:

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.

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.

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.

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:

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.

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

When completing process IDs, for example as arguments to the kill and wait builtins the name of a command may be converted to the appropriate process ID. A problem arises when the process name typed is not unique. By default (or if this style is set explicitly to ` menu') the name will be converted immediately to a set of possible IDs, and menu completion will be started to cycle through them.

insert-tab

If this is set to `true', the completion system will insert a TAB character (assuming that was used to start completion) instead of performing completion when there is no non-blank character to the left of the cursor. If it is set to `false', completion will be done even there.

insert-unambiguous

This is used by the _match and _approximate completers. These completers are often used with menu completion since the word typed may bear little resemblance to the final completion. However, if this style is `true', the completer will start menu completion only if it could find no unambiguous initial string at least as long as the original string typed by the user.

gain-privileges

If set to true, this style enables the use of commands like sudo or doas to gain extra privileges when retrieving information for completion. This is only done when a command such as sudo appears on the command-line. To force the use of, e.g. sudo or to override any prefix that might be added due to gain-privileges, the command style can be used with a value that begins with a hyphen.

keep-prefix

This style is used by the _expand completer. If it is `true', the completer will try to keep a prefix containing a tilde or parameter expansion. Hence, for example, the string ` ~/f*' would be expanded to ` ~/foo' instead of `/home/user/foo'. If the style is set to ` changed' (the default), the prefix will only be left unchanged if there were other changes between the expanded words and the original word from the command line. Any other value forces the prefix to be expanded unconditionally.

last-prompt

This is a more flexible form of the ALWAYS_LAST_PROMPT option. If it is `true', the completion system will try to return the cursor to the previous command line after displaying a completion list. It is tested for all tags valid for the current completion, then the default tag. The cursor will be moved back to the previous line if this style is `true' for all types of match. Note that unlike the ALWAYS_LAST_PROMPT option this is independent of the numeric argument.

known-hosts-files

This style should contain a list of files to search for host names and (if the use-ip style is set) IP addresses in a format compatible with ssh known_hosts files. If it is not set, the files /etc/ssh/ssh_known_hosts and ~/.ssh/known_hosts are used.

list

This style is used by the _history_complete_word bindable command. If it is set to `true' it has no effect. If it is set to `false' matches will not be listed. This overrides the setting of the options controlling listing behaviour, in particular AUTO_LIST. The context always starts with ` :completion:history-words'.

list-colors

If the zsh/complist module is loaded, this style can be used to set color specifications. This mechanism replaces the use of the ZLS_COLORS and ZLS_COLOURS parameters described in the section `The zsh/complist Module' in zshmodules(1), but the syntax is the same.

list-dirs-first

This is used by file completion. If set, directories to be completed are listed separately from and before completion for other files, regardless of tag ordering. In addition, the tag other-files is used in place of all-files for the remaining files, to indicate that no directories are presented with that tag.

list-grouped

If this style is `true' (the default), the completion system will try to make certain completion listings more compact by grouping matches. For example, options for commands that have the same description (shown when the verbose style is set to `true') will appear as a single entry. However, menu selection can be used to cycle through all the matches.

list-packed

This is tested for each tag valid in the current context as well as the default tag. If it is set to `true', the corresponding matches appear in listings as if the LIST_PACKED option were set. If it is set to `false', they are listed normally.

list-prompt

If this style is set for the default tag, completion lists that don't fit on the screen can be scrolled (see the description of the zsh/complist module in zshmodules(1)). The value, if not the empty string, will be displayed after every screenful and the shell will prompt for a key press; if the style is set to the empty string, a default prompt will be used.

list-rows-first

This style is tested in the same way as the list-packed style and determines whether matches are to be listed in a rows-first fashion as if the LIST_ROWS_FIRST option were set.

list-suffixes

This style is used by the function that completes filenames. If it is `true', and completion is attempted on a string containing multiple partially typed pathname components, all ambiguous components will be shown. Otherwise, completion stops at the first ambiguous component.

list-separator

The value of this style is used in completion listing to separate the string to complete from a description when possible (e.g. when completing options). It defaults to ` --' (two hyphens).

local

This is for use with functions that complete URLs for which the corresponding files are available directly from the file system. Its value should consist of three strings: a hostname, the path to the default web pages for the server, and the directory name used by a user placing web pages within their home area.

mail-directory

If set, zsh will assume that mailbox files can be found in the directory specified. It defaults to ` ~/Mail'.

match-original

This is used by the _match completer. If it is set to only, _match will try to generate matches without inserting a ` *' at the cursor position. If set to any other non-empty value, it will first try to generate matches without inserting the ` *' and if that yields no matches, it will try again with the ` *' inserted. If it is unset or set to the empty string, matching will only be performed with the ` *' inserted.

matcher

This style is tested separately for each tag valid in the current context. Its value is placed before any match specifications given by the matcher-list style so can override them via the use of an x: specification. The value should be in the form described in the section `Completion Matching Control' in zshcompwid(1). For examples of this, see the description of the tag-order style.

matcher-list

This style can be set to a list of match specifications that are to be applied everywhere. Match specifications are described in the section `Completion Matching Control' in zshcompwid(1). The completion system will try them one after another for each completer selected. For example, to try first simple completion and, if that generates no matches, case-insensitive completion:

max-errors

This is used by the _approximate and _correct completer functions to determine the maximum number of errors to allow. The completer will try to generate completions by first allowing one error, then two errors, and so on, until either a match or matches were found or the maximum number of errors given by this style has been reached.

max-matches-width

This style is used to determine the trade off between the width of the display used for matches and the width used for their descriptions when the verbose style is in effect. The value gives the number of display columns to reserve for the matches. The default is half the width of the screen.

menu

If this is `true' in the context of any of the tags defined for the current completion menu completion will be used. The value for a specific tag will take precedence over that for the ` default' tag.

muttrc

If set, gives the location of the mutt configuration file. It defaults to ` ~/.muttrc'.

numbers

This is used with the jobs tag. If it is `true', the shell will complete job numbers instead of the shortest unambiguous prefix of the job command text. If the value is a number, job numbers will only be used if that many words from the job descriptions are required to resolve ambiguities. For example, if the value is ` 1', strings will only be used if all jobs differ in the first word on their command lines.

old-list

This is used by the _oldlist completer. If it is set to `always', then standard widgets which perform listing will retain the current list of matches, however they were generated; this can be turned off explicitly with the value ` never', giving the behaviour without the _oldlist completer. If the style is unset, or any other value, then the existing list of completions is displayed if it is not already; otherwise, the standard completion list is generated; this is the default behaviour of _oldlist. However, if there is an old list and this style contains the name of the completer function that generated the list, then the old list will be used even if it was generated by a widget which does not do listing.

old-matches

This is used by the _all_matches completer to decide if an old list of matches should be used if one exists. This is selected by one of the `true' values or by the string ` only'. If the value is ` only', _all_matches will only use an old list and won't have any effect on the list of matches currently being generated.

old-menu

This is used by the _oldlist completer. It controls how menu completion behaves when a completion has already been inserted and the user types a standard completion key such as TAB. The default behaviour of _oldlist is that menu completion always continues with the existing list of completions. If this style is set to `false', however, a new completion is started if the old list was generated by a different completion command; this is the behaviour without the _oldlist completer.

original

This is used by the _approximate and _correct completers to decide if the original string should be added as a possible completion. Normally, this is done only if there are at least two possible corrections, but if this style is set to `true', it is always added. Note that the style will be examined with the completer field in the context name set to correct-num or approximate-num, where num is the number of errors that were accepted.

packageset

This style is used when completing arguments of the Debian `dpkg' program. It contains an override for the default package set for a given context. For example,

path

The function that completes color names uses this style with the colors tag. The value should be the pathname of a file containing color names in the format of an X11 rgb.txt file. If the style is not set but this file is found in one of various standard locations it will be used as the default.

path-completion

This is used by filename completion. By default, filename completion examines all components of a path to see if there are completions of that component. For example, /u/b/z can be completed to /usr/bin/zsh. Explicitly setting this style to `false' inhibits this behaviour for path components up to the / before the cursor; this overrides the setting of accept-exact-dirs.

pine-directory

If set, specifies the directory containing PINE mailbox files. There is no default, since recursively searching this directory is inconvenient for anyone who doesn't use PINE.

ports

A list of Internet service names (network ports) to complete. If this is not set, service names are taken from the file ` /etc/services'.

prefix-hidden

This is used for certain completions which share a common prefix, for example command options beginning with dashes. If it is `true', the prefix will not be shown in the list of matches.

prefix-needed

This style is also relevant for matches with a common prefix. If it is set to `true' this common prefix must be typed by the user to generate the matches.

preserve-prefix

This style is used when completing path names. Its value should be a pattern matching an initial prefix of the word to complete that should be left unchanged under all circumstances. For example, on some Unices an initial ` //' (double slash) has a special meaning; setting this style to the string ` //' will preserve it. As another example, setting this style to ` ?:/' under Cygwin would allow completion after ` a:/...' and so on.

range

This is used by the _history completer and the _history_complete_word bindable command to decide which words should be completed.

recursive-files

If this style is set, its value is an array of patterns to be tested against ` $PWD/': note the trailing slash, which allows directories in the pattern to be delimited unambiguously by including slashes on both sides. If an ordinary file completion fails and the word on the command line does not yet have a directory part to its name, the style is retrieved using the same tag as for the completion just attempted, then the elements tested against $PWD/ in turn. If one matches, then the shell reattempts completion by prepending the word on the command line with each directory in the expansion of **/*(/) in turn. Typically the elements of the style will be set to restrict the number of directories beneath the current one to a manageable number, for example ` */.git/*'.

regular

This style is used by the _expand_alias completer and bindable command. If set to `true' (the default), regular aliases will be expanded but only in command position. If it is set to `false', regular aliases will never be expanded. If it is set to ` always', regular aliases will be expanded even if not in command position.

rehash

If this is set when completing external commands, the internal list (hash) of commands will be updated for each search by issuing the rehash command. There is a speed penalty for this which is only likely to be noticeable when directories in the path have slow file access.

remote-access

If set to `false', certain commands will be prevented from making Internet connections to retrieve remote information. This includes the completion for the CVS command.

remove-all-dups

The _history_complete_word bindable command and the _history completer use this to decide if all duplicate matches should be removed, rather than just consecutive duplicates.

select-prompt

If this is set for the default tag, its value will be displayed during menu selection (see the menu style above) when the completion list does not fit on the screen as a whole. The same escapes as for the list-prompt style are understood, except that the numbers refer to the match or line the mark is on. A default prompt is used when the value is the empty string.

select-scroll

This style is tested for the default tag and determines how a completion list is scrolled during a menu selection (see the menu style above) when the completion list does not fit on the screen as a whole. If the value is ` 0' (zero), the list is scrolled by half-screenfuls; if it is a positive integer, the list is scrolled by the given number of lines; if it is a negative number, the list is scrolled by a screenful minus the absolute value of the given number of lines. The default is to scroll by single lines.

separate-sections

This style is used with the manuals tag when completing names of manual pages. If it is `true', entries for different sections are added separately using tag names of the form ` manual.X', where X is the section number. When the group-name style is also in effect, pages from different sections will appear separately. This style is also used similarly with the words style when completing words for the dict command. It allows words from different dictionary databases to be added separately. The default for this style is `false'.

show-ambiguity

If the zsh/complist module is loaded, this style can be used to highlight the first ambiguous character in completion lists. The value is either a color indication such as those supported by the list-colors style or, with a value of `true', a default of underlining is selected. The highlighting is only applied if the completion display strings correspond to the actual matches.

show-completer

Tested whenever a new completer is tried. If it is `true', the completion system outputs a progress message in the listing area showing what completer is being tried. The message will be overwritten by any output when completions are found and is removed after completion is finished.

single-ignored

This is used by the _ignored completer when there is only one match. If its value is ` show', the single match will be displayed but not inserted. If the value is ` menu', then the single match and the original string are both added as matches and menu completion is started, making it easy to select either of them.

sort

Many completion widgets call _description at some point which decides whether the matches are added sorted or unsorted (often indirectly via _wanted or _requested). This style can be set explicitly to one of the usual `true' or `false' values as an override. If it is not set for the context, the standard behaviour of the calling widget is used.

special-dirs

Normally, the completion code will not produce the directory names ` .' and ` ..' as possible completions. If this style is set to `true', it will add both ` .' and `..' as possible completions; if it is set to ` ..', only `..' will be added.

squeeze-slashes

If set to `true', sequences of slashes in filename paths (for example in ` foo//bar') will be treated as a single slash. This is the usual behaviour of UNIX paths. However, by default the file completion function behaves as if there were a ` *' between the slashes.

stop

If set to `true', the _history_complete_word bindable command will stop once when reaching the beginning or end of the history. Invoking _history_complete_word will then wrap around to the opposite end of the history. If this style is set to `false' (the default), _history_complete_word will loop immediately as in a menu completion.

strip-comments

If set to `true', this style causes non-essential comment text to be removed from completion matches. Currently it is only used when completing e-mail addresses where it removes any display name from the addresses, cutting them down to plain user@host form.

subst-globs-only

This is used by the _expand completer. If it is set to `true', the expansion will only be used if it resulted from globbing; hence, if expansions resulted from the use of the substitute style described below, but these were not further changed by globbing, the expansions will be rejected.

substitute

This boolean style controls whether the _expand completer will first try to expand all substitutions in the string (such as ` $(...)' and `${...}').

suffix

This is used by the _expand completer if the word starts with a tilde or contains a parameter expansion. If it is set to `true', the word will only be expanded if it doesn't have a suffix, i.e. if it is something like ` ~foo' or `$foo' rather than `~foo/' or ` $foo/bar', unless that suffix itself contains characters eligible for expansion. The default for this style is `true'.

tag-order

This provides a mechanism for sorting how the tags available in a particular context will be used.

urls

This is used together with the urls tag by functions completing URLs.

use-cache

If this is set, the completion caching layer is activated for any completions which use it (via the _store_cache, _retrieve_cache, and _cache_invalid functions). The directory containing the cache files can be changed with the cache-path style.

use-compctl

If this style is set to a string not equal to false, 0, no, and off, the completion system may use any completion specifications defined with the compctl builtin command. If the style is unset, this is done only if the zsh/compctl module is loaded. The string may also contain the substring ` first' to use completions defined with ` compctl -T', and the substring ` default' to use the completion defined with ` compctl -D'.

use-ip

By default, the function _hosts that completes host names strips IP addresses from entries read from host databases such as NIS and ssh files. If this style is `true', the corresponding IP addresses can be completed as well. This style is not use in any context where the hosts style is set; note also it must be set before the cache of host names is generated (typically the first completion attempt).

users

This may be set to a list of usernames to be completed. If it is not set all usernames will be completed. Note that if it is set only that list of users will be completed; this is because on some systems querying all users can take a prohibitive amount of time.

users-hosts

The values of this style should be of the form ` user@host' or ` user:host'. It is used for commands that need pairs of user- and hostnames. These commands will complete usernames from this style (only), and will restrict subsequent hostname completion to hosts paired with that user in one of the values of the style.

users-hosts-ports

Like users-hosts but used for commands like telnet and containing strings of the form ` user@host:port'.

verbose

If set, as it is by default, the completion listing is more verbose. In particular many commands show descriptions for options if this style is `true'.

word

This is used by the _list completer, which prevents the insertion of completions until a second completion attempt when the line has not changed. The normal way of finding out if the line has changed is to compare its entire contents between the two occasions. If this style is `true', the comparison is instead performed only on the current word. Hence if completion is performed on another word with the same contents, completion will not be delayed.

CONTROL FUNCTIONS

The initialization script compinit redefines all the widgets which perform completion to call the supplied widget function _main_complete. This function acts as a wrapper calling the so-called `completer' functions that generate matches. If _main_complete is called with arguments, these are taken as the names of completer functions to be called in the order given. If no arguments are given, the set of functions to try is taken from the completer style. For example, to use normal completion and correction if that doesn't generate any matches: after calling compinit. The default value for this style is ` _complete _ignored', i.e. normally only ordinary completion is tried, first with the effect of the ignored-patterns style and then without it. The _main_complete function uses the return status of the completer functions to decide if other completers should be called. If the return status is zero, no other completers are tried and the _main_complete function returns. If the first argument to _main_complete is a single hyphen, the arguments will not be taken as names of completers. Instead, the second argument gives a name to use in the completer field of the context and the other arguments give a command name and arguments to call to generate the matches. The following completer functions are contained in the distribution, although users may write their own. Note that in contexts the leading underscore is stripped, for example basic completion is performed in the context ` :completion::complete: ...'.

_all_matches

This completer can be used to add a string consisting of all other matches. As it influences later completers it must appear as the first completer in the list. The list of all matches is affected by the avoid-completer and old-matches styles described above.

_approximate

This is similar to the basic _complete completer but allows the completions to undergo corrections. The maximum number of errors can be specified by the max-errors style; see the description of approximate matching in zshexpn(1) for how errors are counted. Normally this completer will only be tried after the normal _complete completer:

_canonical_paths [ -A var ] [ -N ] [ -MJV12nfX ] tag descr [ paths ... ]

This completion function completes all paths given to it, and also tries to offer completions which point to the same file as one of the paths given (relative path when an absolute path is given, and vice versa; when ..'s are present in the word to be completed; and some paths got from symlinks).

_cmdambivalent

Completes the remaining positional arguments as an external command. The external command and its arguments are completed as separate arguments (in a manner appropriate for completing /usr/bin/env) if there are two or more remaining positional arguments on the command line, and as a quoted command string (in the manner of system(...)) otherwise. See also _cmdstring and _precommand.

_cmdstring

Completes an external command as a single argument, as for system(...).

_complete

This completer generates all possible completions in a context-sensitive manner, i.e. using the settings defined with the compdef function explained above and the current settings of all special parameters. This gives the normal completion behaviour.

_correct

Generate corrections, but not completions, for the current word; this is similar to _approximate but will not allow any number of extra characters at the cursor as that completer does. The effect is similar to spell-checking. It is based on _approximate, but the completer field in the context name is correct.

_expand

This completer function does not really perform completion, but instead checks if the word on the command line is eligible for expansion and, if it is, gives detailed control over how this expansion is done. For this to happen, the completion system needs to be invoked with complete-word, not expand-or-complete (the default binding for TAB), as otherwise the string will be expanded by the shell's internal mechanism before the completion system is started. Note also this completer should be called before the _complete completer function.

_expand_alias

If the word the cursor is on is an alias, it is expanded and no other completers are called. The types of aliases which are to be expanded can be controlled with the styles regular, global and disabled.

_extensions

If the cursor follows the string `*.', filename extensions are completed. The extensions are taken from files in current directory or a directory specified at the beginning of the current word. For exact matches, completion continues to allow other completers such as _expand to expand the pattern. The standard add-space and prefix-hidden styles are observed.

_external_pwds

Completes current directories of other zsh processes belonging to the current user.

_history

Complete words from the shell's command history. This completer can be controlled by the remove-all-dups, and sort styles as for the _history_complete_word bindable command, see the section `Bindable Commands' below and the section `Completion System Configuration' above.

_ignored

The ignored-patterns style can be set to a list of patterns which are compared against possible completions; matching ones are removed. With this completer those matches can be reinstated, as if no ignored-patterns style were set. The completer actually generates its own list of matches; which completers are invoked is determined in the same way as for the _prefix completer. The single-ignored style is also available as described above.

_list

This completer allows the insertion of matches to be delayed until completion is attempted a second time without the word on the line being changed. On the first attempt, only the list of matches will be shown. It is affected by the styles condition and word, see the section `Completion System Configuration' above.

_match

This completer is intended to be used after the _complete completer. It behaves similarly but the string on the command line may be a pattern to match against trial completions. This gives the effect of the GLOB_COMPLETE option.

_menu

This completer was written as simple example function to show how menu completion can be enabled in shell code. However, it has the notable effect of disabling menu selection which can be useful with _generic based widgets. It should be used as the first completer in the list. Note that this is independent of the setting of the MENU_COMPLETE option and does not work with the other menu completion widgets such as reverse-menu-complete, or accept-and-menu-complete.

_oldlist

This completer controls how the standard completion widgets behave when there is an existing list of completions which may have been generated by a special completion (i.e. a separately-bound completion command). It allows the ordinary completion keys to continue to use the list of completions thus generated, instead of producing a new list of ordinary contextual completions. It should appear in the list of completers before any of the widgets which generate matches. It uses two styles: old-list and old-menu, see the section `Completion System Configuration' above.

_precommand

Complete an external command in word-separated arguments, as for exec and /usr/bin/env.

_prefix

This completer can be used to try completion with the suffix (everything after the cursor) ignored. In other words, the suffix will not be considered to be part of the word to complete. The effect is similar to the expand-or-complete-prefix command.

_user_expand

This completer behaves similarly to the _expand completer but instead performs expansions defined by users. The styles add-space and sort styles specific to the _expand completer are usable with _user_expand in addition to other styles handled more generally by the completion system. The tag all-expansions is also available.

BINDABLE COMMANDS

In addition to the context-dependent completions provided, which are expected to work in an intuitively obvious way, there are a few widgets implementing special behaviour which can be bound separately to keys. The following is a list of these and their default bindings.

_bash_completions

This function is used by two widgets, _bash_complete-word and _bash_list-choices. It exists to provide compatibility with completion bindings in bash. The last character of the binding determines what is completed: ` !', command names; `$', environment variables; ` @', host names; `/', file names; `~' user names. In bash, the binding preceded by ` \e' gives completion, and preceded by ` ^X' lists options. As some of these bindings clash with standard zsh bindings, only ` \e~' and `^X~' are bound by default. To add the rest, the following should be added to .zshrc after compinit has been run:

_correct_filename (^XC)

Correct the filename path at the cursor position. Allows up to six errors in the name. Can also be called with an argument to correct a filename path, independently of zle; the correction is printed on standard output.

_correct_word (^Xc)

Performs correction of the current argument using the usual contextual completions as possible choices. This stores the string ` correct-word' in the function field of the context name and then calls the _correct completer.

_expand_alias (^Xa)

This function can be used as a completer and as a bindable command. It expands the word the cursor is on if it is an alias. The types of alias expanded can be controlled with the styles regular, global and disabled.

_expand_word (^Xe)

Performs expansion on the current word: equivalent to the standard expand-word command, but using the _expand completer. Before calling it, the function field of the context is set to ` expand-word'.

_generic

This function is not defined as a widget and not bound by default. However, it can be used to define a widget and will then store the name of the widget in the function field of the context and call the completion system. This allows custom completion widgets with their own set of style settings to be defined easily. For example, to define a widget that performs normal completion and starts menu selection:

_history_complete_word (\e/)

Complete words from the shell's command history. This uses the list, remove-all-dups, sort, and stop styles.

_most_recent_file (^Xm)

Complete the name of the most recently modified file matching the pattern on the command line (which may be blank). If given a numeric argument N, complete the Nth most recently modified file. Note the completion, if any, is always unique.

_next_tags (^Xn)

This command alters the set of matches used to that for the next tag, or set of tags, either as given by the tag-order style or as set by default; these matches would otherwise not be available. Successive invocations of the command cycle through all possible sets of tags.

_read_comp (^X^R)

Prompt the user for a string, and use that to perform completion on the current word. There are two possibilities for the string. First, it can be a set of words beginning ` _', for example `_files -/', in which case the function with any arguments will be called to generate the completions. Unambiguous parts of the function name will be completed automatically (normal completion is not available at this point) until a space is typed.

_complete_debug (^X?)

This widget performs ordinary completion, but captures in a temporary file a trace of the shell commands executed by the completion system. Each completion attempt gets its own file. A command to view each of these files is pushed onto the editor buffer stack.

_complete_help (^Xh)

This widget displays information about the context names, the tags, and the completion functions used when completing at the current cursor position. If given a numeric argument other than 1 (as in `ESC-2 ^Xh'), then the styles used and the contexts for which they are used will be shown, too.

_complete_help_generic

Unlike other commands listed here, this must be created as a normal ZLE widget rather than a completion widget (i.e. with zle -N). It is used for generating help with a widget bound to the _generic widget that is described above.

_complete_tag (^Xt)

This widget completes symbol tags created by the etags or ctags programmes (note there is no connection with the completion system's tags) stored in a file TAGS, in the format used by etags, or tags, in the format created by ctags. It will look back up the path hierarchy for the first occurrence of either file; if both exist, the file TAGS is preferred. You can specify the full path to a TAGS or tags file by setting the parameter $TAGSFILE or $tagsfile respectively. The corresponding completion tags used are etags and vtags, after emacs and vi respectively.

UTILITY FUNCTIONS

Descriptions follow for utility functions that may be useful when writing completion functions. If functions are installed in subdirectories, most of these reside in the Base subdirectory. Like the example functions for commands in the distribution, the utility functions generating matches all follow the convention of returning status zero if they generated completions and non-zero if no matching completions could be added.

_absolute_command_paths

This function completes external commands as absolute paths (unlike _command_names -e which completes their basenames). It takes no arguments.

_all_labels [ -x ] [ -12VJ ] tag name descr [ command arg ... ]

This is a convenient interface to the _next_label function below, implementing the loop shown in the _next_label example. The command and its arguments are called to generate the matches. The options stored in the parameter name will automatically be inserted into the args passed to the command. Normally, they are put directly after the command, but if one of the args is a single hyphen, they are inserted directly before that. If the hyphen is the last argument, it will be removed from the argument list before the command is called. This allows _all_labels to be used in almost all cases where the matches can be generated by a single call to the compadd builtin command or by a call to one of the utility functions.

_alternative [ -O name ] [ -C name ] spec ...

This function is useful in simple cases where multiple tags are available. Essentially it implements a loop like the one described for the _tags function below.

_arguments [ -nswWCRS ] [ -A pat ] [ -O name ] [ -M matchspec ]

[ : ] spec ...

_arguments [ opt ... ] -- [ -l ] [ -i pats ] [ -s pair ]

[ helpspec ...]

This function can be used to give a complete specification for completion for a command whose arguments follow standard UNIX option and argument conventions.