NAME

DESCRIPTION

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.

HISTORY EXPANSION

Overview

Event Designators

!

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

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 $.

Modifiers

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.

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

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

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

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

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

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

(mycmd =(myoutput)) &!

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

File /tmp/zsh6nU0kS:
This be the verse

PARAMETER EXPANSION

array=("first word" "second word")
scalar="only word"

${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.

${name#pattern}

${name##pattern}

If the pattern matches the beginning of the value of name, then substitute the value of name with the matched portion deleted; otherwise, just substitute the value of name. In the first form, the smallest matching pattern is preferred; in the second form, the largest matching pattern is preferred.

${name%pattern}

${name%%pattern}

If the pattern matches the end of the value of name, then substitute the value of name with the matched portion deleted; otherwise, just substitute the value of name. In the first form, the smallest matching pattern is preferred; in the second form, the largest matching pattern is preferred.

${name:#pattern}

If the pattern matches the value of name, then substitute the empty string; otherwise, just substitute the value of name. If name is an array the matching array elements are removed (use the ` (M)' flag to remove the non-matched elements).

${name:|arrayname}

If arrayname is the name (N.B., not contents) of an array variable, then any elements contained in arrayname are removed from the substitution of name. If the substitution is scalar, either because name is a scalar variable or the expression is quoted, the elements of arrayname are instead tested against the entire expression.

${name:*arrayname}

Similar to the preceding substitution, but in the opposite sense, so that entries present in both the original substitution and as elements of arrayname are retained and others removed.

${name:^arrayname}

${name:^^arrayname}

Zips two arrays, such that the output array is twice as long as the shortest (longest for ` :^^') of name and arrayname, with the elements alternatingly being picked from them. For ` :^', if one of the input arrays is longer, the output will stop when the end of the shorter array is reached. Thus,

a=(1 2 3 4); b=(a b); print ${a:^b}

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

${name:offset}

${name:offset:length}

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

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

${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}.

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

${#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.

Parameter Expansion Flags

#

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.

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

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

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:'.

p

Recognize the same escape sequences as the print builtin in string arguments to any of the flags described below that follow this argument.

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

~

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

[[ "?" = ${(~j.|.)array} ]]

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.

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

Z:opts:

As z but takes a combination of option letters between a following pair of delimiter characters. With no options the effect is identical to z. (Z+c+) causes comments to be parsed as a string and retained; any field in the resulting array beginning with an unquoted comment character is a comment. (Z+C+) causes comments to be parsed and removed. The rule for comments is standard: anything between a word starting with the third character of $HISTCHARS, default #, up to the next newline is a comment. (Z+n+) causes unquoted newlines to be treated as ordinary whitespace, else they are treated as if they are shell code delimiters and converted to semicolons. Options are combined within the same set of delimiters, e.g. (Z+Cn+).

_:flags:

The underscore (_) flag is reserved for future use. As of this revision of zsh, there are no valid flags; anything following an underscore, other than an empty pair of delimiters, is treated as an error, and the flag itself has no effect.

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.

which switch is the right switch for Ipswich?

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

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

"${(@)${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]}".

${(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

ARITHMETIC EXPANSION

BRACE EXPANSION

FILENAME EXPANSION

Dynamic named directories

reply=(s 16)

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

Static named directories

`=' expansion

Notes

FILENAME GENERATION

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

@(...)

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

Globbing Flags

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.

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

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.

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

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.

Approximate Matching

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.

Recursive Globbing

ls (*/)#bar

ls **/bar

setopt GLOBSTARSHORT
ls **.c

ls **/*.c

Glob Qualifiers

/

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).

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

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.

ls *(-/)

ls *(-@)

ls *(%W)

ls *(W,X)

echo /tmp/foo*(u0^@:t)

ls *.*~(lex|parse).[ch](^D^l1)

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