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ZSHEXPN(1) ZSHEXPN(1)
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 zsh-
misc(1).
Process Substitution
Parameter Expansion
Command Substitution
Arithmetic Expansion
Brace Expansion
These five are performed in one step in
left-to-right fashion. After these expansions, all
unquoted occurrences of the characters `\', `'' and
`"' are removed.
Filename Expansion
If the SH_FILE_EXPANSION option is set, the order
of expansion is modified for compatibility with sh
and ksh. In that case filename expansion is per-
formed 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 com-
plicated commands or arguments. Immediately before execu-
tion, 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 Prompt Expansion in zshmisc(1)) is
the number that is to be assigned to the next command.
Overview
A history expansion begins with the first character of the
histchars parameter, which is `!' by default, and may
occur anywhere on the command line; history expansions do
not nest. The `!' can be escaped with `\' or can be
enclosed between a pair of single quotes ('') to suppress
its special meaning. Double quotes will not work for
this. Following this history character is an optional
event designator (see the section `Event Designators') and
then an optional word designator (the section `Word Desig-
nators'); 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 ref-
erences.
By default, a history reference with no event designator
refers to the same event as any preceding history refer-
ence on that command line; if it is the only history ref-
erence 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 `!!$', respectively. Conversely, if CSH_JUNKIE_HIS-
TORY is unset, then `!:1' and `!$' 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 `^'.
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 charac-
ter by setting the histchars parameter.
! Start a history expansion, except when followed by
a blank, newline, `=' or `('. If followed immedi-
ately 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 charac-
ters (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 des-
ignator 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.
h Remove a trailing pathname component, leaving the
head. This works like `dirname'.
r Remove a filename extension of the form `.xxx',
leaving the root name.
e Remove all but the extension.
t Remove all leading pathname components, leaving the
tail. This works like `basename'.
p Print the new command but do not execute it. Only
works with history expansion.
q Quote the substituted words, escaping further sub-
stitutions. Works with history expansion and
parameter expansion, though for parameters it is
only useful if the resulting text is to be re-eval-
uated such as by eval.
Q Remove one level of quotes from the substituted
words.
x Like q, but break into words at whitespace. Does
not work with parameter expansion.
l Convert the words to all lowercase.
u Convert the words to all uppercase.
s/l/r[/]
Substitute r for l as described below. Unless pre-
ceded immediately by a g, with no colon between,
the substitution is done only for the first string
that matches l. For arrays and for filename gener-
ation, this applies to each word of the expanded
text.
& Repeat the previous s substitution. Like s, may be
preceded immediately by a g. In parameter expan-
sion the & must appear inside braces, and in file-
name generation it must be quoted with a backslash.
The s/l/r/ substitution works as follows. The left-hand
side of substitutions are not regular expressions, but
character strings. Any character can be used as the
delimiter in place of `/'. A backslash quotes the delim-
iter 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 omit-
ted. Note the same record of the last l and r is main-
tained across all forms of expansion.
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 command argument of the form `<(list)', `>(list)' or
`=(list)' is subject to process substitution. In the case
of the < or > forms, the shell runs process list asyn-
chronously. If the system supports the /dev/fd mechanism,
the command argument is the name of the device file corre-
sponding 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 con-
nected to the output of the list process. For example,
paste <(cut -f1 file1) <(cut -f3 file2) |
tee >(process1) >(process2) >/dev/null
cuts fields 1 and 3 from the files file1 and file2 respec-
tively, 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 con-
taining 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.
The = form is useful as both the /dev/fd and the named
pipe implementation of <(...) have drawbacks. In the for-
mer 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 secu-
rity 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, dif-
ferent operating systems may have different behaviour)
block for ever and have to be killed explicitly. In both
cases, the shell actually supplies the information using a
pipe, so that programmes that expect to lseek (see
lseek(2)) on the file will not work.
Also note that the previous example can be more compactly
and efficiently written (provided the MULTIOS option is
set) as:
paste <(cut -f1 file1) <(cut -f3 file2) \
> >(process1) > >(process2)
The shell uses pipes instead of FIFOs to implement the
latter two process substitutions in the above example.
There is an additional problem with >(process); when this
is attached to an external command, the parent shell does
not wait for process to finish and hence an immediately
following command cannot rely on the results being com-
plete. The problem and solution are the same as described
in the section MULTIOS in zshmisc(1). Hence in a simpli-
fied version of the example above:
paste <(cut -f1 file1) <(cut -f3 file2) > >(process)
(note that no MULTIOS are involved), process will be run
asynchronously. The workaround is:
{ paste <(cut -f1 file1) <(cut -f3 file2) } > >(process)
The extra processes here are spawned from the parent shell
which will wait for their completion.
PARAMETER EXPANSION
The character `$' is used to introduce parameter expan-
sions. See zshparam(1) for a description of parameters,
including arrays, associative arrays, and subscript nota-
tion to access individual array elements.
Note in particular the fact that words of unquoted parame-
ters 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 file-
name 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 modi-
fiers described in the section `Modifiers' in the section
`History Expansion' can be applied: for example,
${i:s/foo/bar/} performs string substitution on the expan-
sion of parameter $i.
${name}
The value, if any, of the parameter name is substi-
tuted. 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; excep-
tions, which only apply if the option KSH_ARRAYS is
not set, are a single subscript or any colon modi-
fiers appearing after the name, or any of the char-
acters `^', `=', `~', `#' or `+' appearing before
the name, all of which work with or without braces.
If name is an array parameter, and the KSH_ARRAYS
option is not set, then the value of each element
of name is substituted, one element per word. Oth-
erwise, the expansion results in one word only;
with KSH_ARRAYS, this is the first element of an
array. No field splitting is done on the result
unless the SH_WORD_SPLIT option is set.
${+name}
If name is the name of a set parameter `1' is sub-
stituted, otherwise `0' is substituted.
${name:-word}
If name is set and is non-null then substitute its
value; otherwise substitute word. If name is miss-
ing, substitute word.
${name:=word}
${name::=word}
In the first form, if name is unset or is null then
set it to word; in the second form, unconditionally
set name to word. In both forms, the value of the
parameter is then substituted.
${name:?word}
If name is set and is 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 mes-
sage is printed.
${name:+word}
If name is set and is non-null then substitute
word; otherwise substitute nothing.
If the colon is omitted from one of the above expressions
containing a colon, then the shell only checks whether
name is set, not whether its value is null.
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 sub-
stitute the empty string; otherwise, just substi-
tute 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/pattern/repl}
${name//pattern/repl}
Replace the longest possible match of pattern in
the expansion of parameter name by string repl.
The first form replaces just the first occurrence,
the second form all occurrences. Both pattern and
repl are subject to double-quoted substitution, so
that expressions like ${name/$opat/$npat} will
work, but note the usual rule that pattern charac-
ters in $opat are not treated specially unless
either the option GLOB_SUBST is set, or $opat is
instead substituted as ${~opat}.
The pattern may begin with a `#', in which case the
pattern must match at the start of the string, or
`%', in which case it must match at the end of the
string. The repl may be an empty string, in which
case the final `/' may also be omitted. To quote
the final `/' in other cases it should be preceded
by a single backslash; this is not necessary if the
`/' occurs inside a substituted parameter. Note
also that the `#' and `%' are not active if they
occur inside a substituted parameter, even at the
start.
The first `/' may be preceded by a `:', in which
case the match will only succeed if it matches the
entire word. Note also the effect of the I and S
parameter expansion flags below; however, the flags
M, R, B, E and N are not useful.
For example,
foo="twinkle twinkle little star" sub="t*e" rep="spy"
print ${foo//${~sub}/$rep}
print ${(S)foo//${~sub}/$rep}
Here, the `~' ensures that the text of $sub is
treated as a pattern rather than a plain string.
In the first case, the longest match for t*e is
substituted and the result is `spy star', while in
the second case, the shortest matches are taken and
the result is `spy spy lispy star'.
${#spec}
If spec is one of the above substitutions, substi-
tute the length in characters of the result instead
of the result itself. If spec is an array expres-
sion, substitute the number of elements of the
result. Note that `^', `=', and `~', below, must
appear to the left of `#' when these forms are com-
bined.
${^spec}
Turn on the RC_EXPAND_PARAM option for the evalua-
tion of spec; if the `^' is doubled, turn it off.
When this option is set, array expansions of the
form foo${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'.
Internally, each such expansion is converted into
the equivalent list for brace expansion. E.g.,
${^var} becomes {$var[1],$var[2],...}, and is pro-
cessed as described in the section `Brace Expan-
sion' below. If word splitting is also in effect
the $var[N] may themselves be split into different
list elements.
${=spec}
Perform word splitting using the rules for
SH_WORD_SPLIT during the evaluation of spec, but
regardless of whether the parameter appears in dou-
ble quotes; if the `=' is doubled, turn it off.
This forces parameter expansions to be split into
separate words before substitution, using IFS as a
delimiter. This is done by default in most other
shells.
Note that splitting is applied to word in the
assignment forms of spec before the assignment to
name is performed. This affects the result of
array assignments with the A flag.
${~spec}
Turn on the GLOB_SUBST option for the evaluation of
spec; if the `~' is doubled, turn it off. When
this option is set, the string resulting from the
expansion will be interpreted as a pattern anywhere
that is possible, such as in filename expansion and
filename generation and pattern-matching contexts
like the right hand side of the `=' and `!=' opera-
tors 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 fol-
lowed by a subscript expression as described in Array
Parameters in zshparam(1).
Note that double quotes may appear around nested expres-
sions, 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 $(foo) as before.
Parameter Expansion Flags
If the opening brace is directly followed by an opening
parenthesis, the string up to the matching closing paren-
thesis will be taken as a list of flags. In cases where
repeating a flag is meaningful, the repetitions need not
be consecutive; for example, `(q%q%q)' means the same
thing as the more readable `(%%qqq)'. The following flags
are supported:
% Expand all % escapes in the resulting words in the
same way as in in prompts (see the section `Prompt
Expansion'). If this flag is given twice, full
prompt expansion is done on the resulting words,
depending on the setting of the PROMPT_PERCENT,
PROMPT_SUBST and PROMPT_BANG options.
@ In double quotes, array elements are put into sepa-
rate words. E.g., `"${(@)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 the f, s or z flags, which still
applies within each array element.
A Create an array parameter with `${...=...}',
`${...:=...}' or `${...::=...}'. If this flag is
repeated (as in `AA'), create an associative array
parameter. Assignment is made before sorting or
padding. The name part may be a subscripted range
for ordinary arrays; the word part must be con-
verted to an array, for example by using
`${(AA)=name=...}' to activate field splitting,
when creating an associative array.
a With o or O, sort in array index order. Note that
`oa' is therefore equivalent to the default but
`Oa' is useful for obtaining an array's elements in
reverse order.
c With ${#name}, count the total number of characters
in an array, as if the elements were concatenated
with spaces between them.
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.
e Perform parameter expansion, command substitution
and arithmetic expansion on the result. Such expan-
sions can be nested but too deep recursion may have
unpredictable effects.
f Split the result of the expansion to lines. 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:'.
i With o or O, sort case-independently.
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 sub-
stituted even if the subscript form refers to val-
ues. However, this flag may not be combined with
subscript ranges.
L Convert all letters in the result to lower case.
n With o or O, sort numerically.
o Sort the resulting words in ascending order.
O Sort the resulting words in descending order.
P This forces the value of the parameter name to be
interpreted as a further parameter name, whose
value will be used where appropriate. If used with
a nested parameter or command substitution, the
result of that will be taken as a parameter name in
the same way. For example, if you have `foo=bar'
and `bar=baz', the strings ${(P)foo}, ${(P)${foo}},
and ${(P)$(echo bar)} will be expanded to `baz'.
q Quote the resulting words with backslashes. If this
flag is given twice, the resulting words are quoted
in single quotes and if it is given three times,
the words are quoted in double quotes. If it is
given four times, the words are quoted in single
quotes preceded by a $.
Q Remove one level of quotes from the resulting
words.
t Use a string describing the type of the parameter
where the value of the parameter would usually
appear. This string consists of keywords separated
by hyphens (`-'). The first keyword in the string
describes the main type, it can be one of `scalar',
`array', `integer', `float' or `association'. The
other keywords describe the type in more detail:
local for local parameters
left for left justified parameters
right_blanks
for right justified parameters with leading
blanks
right_zeros
for right justified parameters with leading
zeros
lower for parameters whose value is converted to
all lower case when it is expanded
upper for parameters whose value is converted to
all upper case when it is expanded
readonly
for readonly parameters
tag for tagged parameters
export for exported parameters
unique for arrays which keep only the first occur-
rence of duplicated values
hide for parameters with the `hide' flag
special
for special parameters defined by the shell
u Expand only the first occurrence of each unique
word.
U Convert all letters in the result to upper case.
v Used with k, substitute (as two consecutive words)
both the key and the value of each associative
array element. Used with subscripts, force values
to be substituted even if the subscript form refers
to indices or keys.
V Make any special characters in the resulting words
visible.
w With ${#name}, count words in arrays or strings;
the s flag may be used to set a word delimiter.
W Similar to w with the difference that empty words
between repeated delimiters are also counted.
X With this flag parsing errors occurring with the Q
and e flags or the pattern matching forms such as
`${name#pattern}' are reported. Without the flag
they 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.
Note that this is done very late, as for the `(s)'
flag. So to access single words in the result, one
has to use nested expansions as in
`${${(z)foo}[2]}'. Likewise, to remove the quotes
in the resulting words one would do:
`${(Q)${(z)foo}}'.
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.
j:string:
Join the words of arrays together using string as a
separator. Note that this occurs before field
splitting by the SH_WORD_SPLIT option.
l:expr::string1::string2:
Pad the resulting words on the left. Each word
will be truncated if required and placed in a field
expr characters wide. The space to the left will
be filled with string1 (concatenated as often as
needed) or spaces if string1 is not given. If both
string1 and string2 are given, this string is
inserted once directly to the left of each word,
before padding.
r:expr::string1::string2:
As l, but pad the words on the right and insert
string2 on the right.
s:string:
Force field splitting (see the option
SH_WORD_SPLIT) at the separator string. Note that
a string of two or more characters means all must
all match in sequence; this differs from the treat-
ment of two or more characters in the IFS parame-
ter.
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 sub-
strings, either with the S flag, or with ${.../...}
(only the exprth match is substituted) or
${...//...} (all matches from the exprth on are
substituted). The default is to take the first
match.
The exprth match is counted such that there is
either one or zero matches from each starting posi-
tion in the string, although for global substitu-
tion matches overlapping previous replacements are
ignored. With the ${...%...} and ${...%%...}
forms, the starting position for the match moves
backwards from the end as the index increases,
while with the other forms it moves forward from
the start.
Hence with the string
which switch is the right switch for Ipswich?
substitutions of the form ${(SI:N:)string#w*ch} as
N increases from 1 will match and remove `which',
`witch', `witch' and `wich'; the form using `##'
will match and remove `which switch is the right
switch for Ipswich', `witch is the right switch for
Ipswich', `witch for Ipswich' and `wich'. The form
using `%' will remove the same matches as for `#',
but in reverse order, and the form using `%%' will
remove the same matches as for `##' in reverse
order.
B Include the index of the beginning of the match in
the result.
E Include the index of the end of the match in the
result.
M Include the matched portion in the result.
N Include the length of the match in the result.
R Include the unmatched portion in the result (the
Rest).
Rules
Here is a summary of the rules for substitution; this
assumes that braces are present around the substitution,
i.e. ${...}. Some particular examples are given below.
Note that the Zsh Development Group accepts no responsi-
bility for any brain damage which may occur during the
reading of the following rules.
1. Nested Substitution
If multiple nested ${...} forms are present, sub-
stitution 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 substitu-
tion will return either a scalar or an array as
determined by the flags, possibly adjusted for
quoting. All the following steps take place where
applicable at all levels of substitution. Note
that, unless the `(P)' flag is present, the flags
and any subscripts apply directly to the value of
the nested substitution; for example, the expansion
${${foo}} behaves exactly the same as ${foo}.
2. Parameter Subscripting
If the value is a raw parameter reference with a
subscript, such as ${var[3]}, the effect of sub-
scripting 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 num-
ber of subscripts may appear.
3. Parameter Name Replacement
The effect of any (P) flag, which treats the value
so far as a parameter name and replaces it with the
corresponding value, is applied.
4. Double-Quoted Joining
If the value after this process is an array, and
the substitution appears in double quotes, and no
(@) flag is present at the current level, the 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 join-
ing instead of $IFS.
5. Nested Subscripting
Any remaining subscripts (i.e. of a nested substi-
tution) are evaluated at this point, based on
whether the value is an array or a scalar. As with
2., 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).
6. 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.
7. Forced Joining
If the `(j)' flag is present, or no `(j)' flag is
present but the string is to be split as given by
rules 8. or 9., and joining did not take place at
step 4., 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.
8. Forced Splitting
If one of the `(s)', `(f)' or `(z)' flags are pre-
sent, 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.
9. Shell Word Splitting
If no `(s)', `(f)' or `=' was given, but the word
is not quoted and the option SH_WORD_SPLIT is set,
the word is split on occurrences of any of the
characters in $IFS. Note this step, too, takes
place at all levels of a nested substitution.
10. Uniqueness
If the result is an array and the `(u)' flag was
present, duplicate elements are removed from the
array.
11. Ordering
If the result is still an array and one of the
`(o)' or `(O)' flags was present, the array is
reordered.
12. Re-Evaluation
Any `(e)' flag is applied to the value, forcing it
to be re-examined for new parameter substitutions,
but also for command and arithmetic substitutions.
13. Padding
Any padding of the value by the `(l.fill.)' or
`(r.fill.)' flags is applied.
14. Semantic Joining
In contexts where expansion semantics requires a
single word to result, all words are rejoined with
the first character of IFS between. So in
`${(P)${(f)lines}}' the value of ${lines} is split
at newlines, but then must be joined again before
the P flag can be applied.
If a single word is not required, this rule is
skipped.
Examples
The flag f is useful to split a double-quoted substitution
line by line. For example, ${(f)"$(ctype(3). Note that the square
brackets are additional to those enclosing the
whole set of characters, so to test for a single
alphanumeric character you need `[[:alnum:]]'.
Named character sets can be used alongside other
types, e.g. `[[:alpha:]0-9]'.
[^...]
[!...] Like [...], except that it matches any character
which is not in the given set.
<[x]-[y]>
Matches any number in the range x to y, inclusive.
Either of the numbers may be omitted to make the
range open-ended; hence `<->' matches any number.
To match individual digits, the [...] form is more
efficient.
Be careful when using other wildcards adjacent to
patterns of this form; for example, <0-9>* will
actually match any number whatsoever at the start
of the string, since the `<0-9>' will match the
first digit, and the `*' will match any others.
This is a trap for the unwary, but is in fact an
inevitable consequence of the rule that the longest
possible match always succeeds. Expressions such
as `<0-9>[^[:digit:]]*' can be used instead.
(...) Matches the enclosed pattern. This is used for
grouping. If the KSH_GLOB option is set, then a
`@', `*', `+', `?' or `!' immediately preceding the
`(' is treated specially, as detailed below. The
option SH_GLOB prevents bare parentheses from being
used in this way, though the KSH_GLOB option is
still available.
Note that grouping cannot extend over multiple
directories: it is an error to have a `/' within a
group (this only applies for patterns used in file-
name generation). There is one exception: a group
of the form (pat/)# appearing as a complete path
segment can match a sequence of directories. For
example, foo/(a*/)#bar matches foo/bar,
foo/any/bar, foo/any/anyother/bar, and so on.
x|y Matches either x or y. This operator has lower
precedence than any other. The `|' character must
be within parentheses, to avoid interpretation as a
pipeline.
^x (Requires EXTENDED_GLOB to be set.) Matches any-
thing 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 opera-
tor 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.
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 `(...)#'.)
+(...) Match at least one occurrence. (Like `(...)##'.)
?(...) 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 pre-
ceding unit (i.e. a character, `?', `[...]', `<...>', or a
parenthesised expression). As mentioned above, a `/' used
as a directory separator may not appear inside parenthe-
ses, 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 spe-
cial; 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 charac-
ters.
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 genera-
tion. When a pattern with a set of active paren-
theses 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 refer-
enced.
For example,
foo="a string with a message"
if [[ $foo = (a|an)' '(#b)(*)' '* ]]; then
print ${foo[$mbegin[1],$mend[1]]}
fi
prints `string with a'. Note that the first paren-
thesis is before the (#b) and does not create a
backreference.
Backreferences work with all forms of pattern
matching other than filename generation, but note
that when performing matches on an entire array,
such as ${array#pattern}, or a global substitution,
such as ${param//pat/repl}, only the data for the
last match remains available. In the case of
global replacements this may still be useful. See
the example for the m flag below.
The numbering of backreferences strictly follows
the order of the opening parentheses from left to
right in the pattern string, although sets of
parentheses may be nested. There are special rules
for parentheses followed by `#' or `##'. Only the
last match of the parenthesis is remembered: for
example, in `[[ abab = (#b)([ab])# ]]', only the
final `b' is stored in match[1]. Thus extra paren-
theses may be necessary to match the complete seg-
ment: for example, use `X((ab|cd)#)Y' to match a
whole string of either `ab' or `cd' between `X' and
`Y', using the value of $match[1] rather than
$match[2].
If the match fails none of the parameters is
altered, so in some cases it may be necessary to
initialise them beforehand. If some of the back-
references fail to match --- which happens if they
are in an alternate branch which fails to match, or
if they are followed by # and matched zero times
--- then the matched string is set to the empty
string, and the start and end indices are set to
-1.
Pattern matching with backreferences is slightly
slower than without.
B Deactivate backreferences, negating the effect of
the b flag from that point on.
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, $MBE-
GIN and $MEND will be set to the string matched and
to the indices of the beginning and end of the
string, respectively. This is most useful in
parameter substitutions, as otherwise the string
matched is obvious.
For example,
arr=(veldt jynx grimps waqf zho buck)
print ${arr//(#m)[aeiou]/${(U)MATCH}}
forces all the matches (i.e. all vowels) into
uppercase, printing `vEldt jynx grImps wAqf zhO
bUck'.
Unlike backreferences, there is no speed penalty
for using match references, other than the extra
substitutions required for the replacement strings
in cases such as the example shown.
M Deactivate the m flag, hence no references to match
data will be created.
anum Approximate matching: num errors are allowed in the
string matched by the pattern. The rules for this
are described in the next subsection.
s, e Unlike the other flags, these have only a local
effect, and each must appear on its own: `(#s)'
and `(#e)' are the only valid forms. The `(#s)'
flag succeeds only at the start of the test string,
and the `(#e)' flag succeeds only at the end of the
test string; they correspond to `^' and `$' in
standard regular expressions. They are useful for
matching path segments in patterns other than those
in filename generation (where path segments are in
any case treated separately). For example,
`*((#s)|/)test((#e)|/)*' matches a path segment
`test' in any of the following strings: test,
test/at/start, at/end/test, in/test/middle.
Another use is in parameter substitution; for exam-
ple `${array/(#s)A*Z(#e)}' will remove only ele-
ments of an array which match the complete pattern
`A*Z'. There are other ways of performing many
operations of this type, however the combination of
the substitution operations `/' and `//' with the
`(#s)' and `(#e)' flags provides a single simple
and memorable method.
Note that assertions of the form `(^(#s))' also
work, i.e. match anywhere except at the start of
the string, although this actually means `anything
except a zero-length portion at the start of the
string'; you need to use `(""~(#s))' to match a
zero-length portion of the string not at the start.
q A `q' and everything up to the closing parenthesis
of the globbing flags are ignored by the pattern
matching code. This is intended to support the use
of glob qualifiers, see below. The result is that
the pattern `(#b)(*).c(#q.)' can be used both for
globbing and for matching against a string. In the
former case, the `(#q.)' will be treated as a glob
qualifier and the `(#b)' will not be useful, while
in the latter case the `(#b)' is useful for back-
references and the `(#q.)' will be ignored. Note
that colon modifiers in the glob qualifiers are
also not applied in ordinary pattern matching.
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 direc-
tory 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 pat-
tern, 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 pat-
tern 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 exam-
ple, (#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 exam-
ple, (#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 with-
out 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 pat-
tern foo.
As a shorthand, `**/' is equivalent to `(*/)#'; note that
this therefore matches files in the current directory as
well as subdirectories. Thus:
ls (*/)#bar
or
ls **/bar
does a recursive directory search for files named `bar'
(potentially including the file `bar' in the current
directory). This form does not follow symbolic links; the
alternative form `***/' does, but is otherwise identical.
Neither of these can be combined with other forms of glob-
bing within the same path segment; in that case, the `*'
operators revert to their usual effect.
Glob Qualifiers
Patterns used for filename generation may end in a list of
qualifiers enclosed in parentheses. The qualifiers spec-
ify 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 paren-
theses, 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 pat-
tern. 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 recog-
nised 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.
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)
% device files (character or block special)
%b block special files
%c character special files
r owner-readable files (0400)
w owner-writable files (0200)
x owner-executable files (0100)
A group-readable files (0040)
I group-writable files (0020)
E group-executable files (0010)
R world-readable files (0004)
W world-writable files (0002)
X world-executable files (0001)
s setuid files (04000)
S setgid files (02000)
t files with the sticky bit (01000)
fspec files with access rights matching spec. This spec
may be a octal number optionally preceded by a `=',
a `+', or a `-'. If none of these characters is
given, the behavior is the same as for `='. The
octal number describes the mode bits to be
expected, if combined with a `=', the value given
must match the file-modes exactly, with a `+', at
least the bits in the given number must be set in
the file-modes, and with a `-', the bits in the
number must not be set. Giving a `?' instead of a
octal digit anywhere in the number ensures that the
corresponding bits in the file-modes are not
checked, this is only useful in combination with
`='.
If the qualifier `f' is followed by any other char-
acter anything up to the next matching character
(`[', `{', and `<' match `]', `}', and `>' respec-
tively, any other character matches itself) is
taken as a list of comma-separated sub-specs. Each
sub-spec may be either an octal number as described
above or a list of any of the characters `u', `g',
`o', and `a', followed by a `=', a `+', or a `-',
followed by a list of any of the characters `r',
`w', `x', `s', and `t', or an octal digit. The
first list of characters specify which access
rights are to be checked. If a `u' is given, those
for the owner of the file are used, if a `g' is
given, those of the group are checked, a `o' means
to test those of other users, and the `a' says to
test all three groups. The `=', `+', and `-' again
says how the modes are to be checked and have the
same meaning as described for the first form above.
The second list of characters finally says which
access rights are to be expected: `r' for read
access, `w' for write access, `x' for the right to
execute the file (or to search a directory), `s'
for the setuid and setgid bits, and `t' for the
sticky bit.
Thus, `*(f70?)' gives the files for which the owner
has read, write, and execute permission, and for
which other group members have no rights, indepen-
dent of the permissions for other users. The pat-
tern `*(f-100)' gives all files for which the owner
does not have execute permission, and
`*(f:gu+w,o-rx:)' gives the files for which the
owner and the other members of the group have at
least write permission, and for which other users
don't have read or execute permission.
estring
+cmd The string will be executed as shell code. The
filename will be included in the list if and only
if the code returns a zero status (usually the sta-
tus of the last command). The first character
after the `e' will be used as a separator and any-
thing up to the next matching separator will be
taken as the string; `[', `{', and `<' match `]',
`}', and `>', respectively, while any other charac-
ter matches itself. Note that expansions must be
quoted in the string to prevent them from being
expanded before globbing is done.
During the execution of string the filename cur-
rently being tested is available in the parameter
REPLY; the parameter may be altered to a string to
be inserted into the list instead of the original
filename. In addition, the parameter reply may be
set to an array or a string, which overrides the
value of REPLY. If set to an array, the latter is
inserted into the command line word by word.
For example, suppose a directory contains a single
file `lonely'. Then the expression
`*(e:'reply=(${REPLY}{1,2})':)' will cause the
words `lonely1 lonely2' to be inserted into the
command line. Note the quotation marks.
The form +cmd has the same effect, but no delim-
iters appear around cmd. Instead, cmd is taken as
the longest sequence of characters following the +
that are alphanumeric or underscore. Typically cmd
will be the name of a shell function that contains
the appropriate test. For example,
nt() { [[ $REPLY -nt $NTREF ]] }
NTREF=reffile
ls -l *(+nt)
lists all files in the directory that have been
modified more recently than reffile.
ddev files on the device dev
l[-|+]ct
files having a link count less than ct (-), greater
than ct (+), or equal to ct
U files owned by the effective user ID
G files owned by the effective group ID
uid files owned by user ID id if it is a number, if
not, than the character after the `u' will be used
as a separator and the string between it and the
next matching separator (`[', `{', and `<' match
`]', `}', and `>' respectively, any other character
matches itself) will be taken as a user name, and
the user ID of this user will be taken (e.g.
`u:foo:' or `u[foo]' for 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 nega-
tive 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 sec-
onds instead of days, respectively. For instance,
`echo *(ah-5)' would echo files accessed within the
last five hours.
m[Mwhms][-|+]n
like the file access qualifier, except that it uses
the file modification time.
c[Mwhms][-|+]n
like the file access qualifier, except that it uses
the file inode change time.
L[+|-]n
files less than n bytes (-), more than n bytes (+),
or exactly n bytes in length. If this flag is
directly followed by a `k' (`K'), `m' (`M'), or `p'
(`P') (e.g. `Lk-50') the check is performed with
kilobytes, megabytes, or blocks (of 512 bytes)
instead.
^ negates all qualifiers following it
- toggles between making the qualifiers work on sym-
bolic 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
oc specifies how the names of the files should be
sorted. If c is n they are sorted by name (the
default); 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, modifi-
cation, or inode change respectively; if d, files
in subdirectories appear before those in the cur-
rent 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. 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.
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 parame-
ter 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.
More than one of these lists can be combined, separated by
commas. The whole list matches if at least one of the sub-
lists matches (they are `or'ed, the qualifiers in the sub-
lists 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'). Note that each modifier must be introduced
by a separate `:'. Note also that the result after modi-
fication 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 per-
formed. Thus:
ls *(-/)
lists all directories and symbolic links that point to
directories, and
ls *(%W)
lists all world-writable device files in the current
directory, and
ls *(W,X)
lists all files in the current directory that are
world-writable or world-executable, and
echo /tmp/foo*(u0^@:t)
outputs the basename of all root-owned files beginning
with the string `foo' in /tmp, ignoring symlinks, and
ls *.*~(lex|parse).[ch](^D^l1)
lists all files having a link count of one whose names
contain a dot (but not those starting with a dot, since
GLOB_DOTS is explicitly switched off) except for lex.c,
lex.h, parse.c and parse.h.
print b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)
demonstrates how colon modifiers and other qualifiers may
be chained together. The ordinary qualifier `.' is
applied first, then the colon modifiers in order from left
to right. So if EXTENDED_GLOB is set and the base pattern
matches the regular file builtin.pro, the shell will print
`shmiltin.shmo'.
zsh 4.2.5 April 6, 2005 ZSHEXPN(1)