1ZSHEXPN(1) General Commands Manual ZSHEXPN(1)
2
6 zshexpn - zsh expansion and substitution
7
9 The following types of expansions are performed in the indicated order
10 in five steps:
11 History Expansion
13 This is performed only in interactive shells.
14 Alias Expansion
16 Aliases are expanded immediately before the command line is
17 parsed as explained under Aliasing in zshmisc(1).
18 Process Substitution
20 Parameter Expansion
21 Command Substitution
22 Arithmetic Expansion
23 Brace Expansion
24 These five are performed in left-to-right fashion. On each ar‐
25 gument, any of the five steps that are needed are performed one
26 after the other. Hence, for example, all the parts of parameter
27 expansion are completed before command substitution is started.
28 After these expansions, all unquoted occurrences of the charac‐
29 ters `\',`'' and `"' are removed.
30 Filename Expansion
32 If the SH_FILE_EXPANSION option is set, the order of expansion
33 is modified for compatibility with sh and ksh. In that case
34 filename expansion is performed immediately after alias expan‐
35 sion, preceding the set of five expansions mentioned above.
36 Filename Generation
38 This expansion, commonly referred to as globbing, is always done
39 last.
40 The following sections explain the types of expansion in detail.
42
44 History expansion allows you to use words from previous command lines
45 in the command line you are typing. This simplifies spelling correc‐
46 tions and the repetition of complicated commands or arguments.
47 Immediately before execution, each command is saved in the history
49 list, the size of which is controlled by the HISTSIZE parameter. The
50 one most recent command is always retained in any case. Each saved
51 command in the history list is called a history event and is assigned a
52 number, beginning with 1 (one) when the shell starts up. The history
53 number that you may see in your prompt (see EXPANSION OF PROMPT SE‐
54 QUENCES in zshmisc(1)) is the number that is to be assigned to the next
55 command.
56 Overview
58 A history expansion begins with the first character of the histchars
59 parameter, which is `!' by default, and may occur anywhere on the com‐
60 mand line, including inside double quotes (but not inside single quotes
61 '...' or C-style quotes $'...' nor when escaped with a backslash).
62 The first character is followed by an optional event designator (see
64 the section `Event Designators') and then an optional word designator
65 (the section `Word Designators'); if neither of these designators is
66 present, no history expansion occurs.
67 Input lines containing history expansions are echoed after being ex‐
69 panded, but before any other expansions take place and before the com‐
70 mand is executed. It is this expanded form that is recorded as the
71 history event for later references.
72 History expansions do not nest.
74 By default, a history reference with no event designator refers to the
76 same event as any preceding history reference on that command line; if
77 it is the only history reference in a command, it refers to the previ‐
78 ous command. However, if the option CSH_JUNKIE_HISTORY is set, then
79 every history reference with no event specification always refers to
80 the previous command.
81 For example, `!' is the event designator for the previous command, so
83 `!!:1' always refers to the first word of the previous command, and
84 `!!$' always refers to the last word of the previous command. With
85 CSH_JUNKIE_HISTORY set, then `!:1' and `!$' function in the same manner
86 as `!!:1' and `!!$', respectively. Conversely, if CSH_JUNKIE_HISTORY
87 is unset, then `!:1' and `!$' refer to the first and last words, re‐
88 spectively, of the same event referenced by the nearest other history
89 reference preceding them on the current command line, or to the previ‐
90 ous command if there is no preceding reference.
91 The character sequence `^foo^bar' (where `^' is actually the second
93 character of the histchars parameter) repeats the last command, replac‐
94 ing the string foo with bar. More precisely, the sequence `^foo^bar^'
95 is synonymous with `!!:s^foo^bar^', hence other modifiers (see the sec‐
96 tion `Modifiers') may follow the final `^'. In particular,
97 `^foo^bar^:G' performs a global substitution.
98 If the shell encounters the character sequence `!"' in the input, the
100 history mechanism is temporarily disabled until the current list (see
101 zshmisc(1)) is fully parsed. The `!"' is removed from the input, and
102 any subsequent `!' characters have no special significance.
103 A less convenient but more comprehensible form of command history sup‐
105 port is provided by the fc builtin.
106 Event Designators
108 An event designator is a reference to a command-line entry in the his‐
109 tory list. In the list below, remember that the initial `!' in each
110 item may be changed to another character by setting the histchars pa‐
111 rameter.
112 ! Start a history expansion, except when followed by a blank, new‐
114 line, `=' or `('. If followed immediately by a word designator
115 (see the section `Word Designators'), this forms a history ref‐
116 erence with no event designator (see the section `Overview').
117 !! Refer to the previous command. By itself, this expansion re‐
119 peats the previous command.
120 !n Refer to command-line n.
122 !-n Refer to the current command-line minus n.
124 !str Refer to the most recent command starting with str.
126 !?str[?]
128 Refer to the most recent command containing str. The trailing
129 `?' is necessary if this reference is to be followed by a modi‐
130 fier or followed by any text that is not to be considered part
131 of str.
132 !# Refer to the current command line typed in so far. The line is
134 treated as if it were complete up to and including the word be‐
135 fore the one with the `!#' reference.
136 !{...} Insulate a history reference from adjacent characters (if neces‐
138 sary).
139 Word Designators
141 A word designator indicates which word or words of a given command line
142 are to be included in a history reference. A `:' usually separates the
143 event specification from the word designator. It may be omitted only
144 if the word designator begins with a `^', `$', `*', `-' or `%'. Word
145 designators include:
146 0 The first input word (command).
148 n The nth argument.
149 ^ The first argument. That is, 1.
150 $ The last argument.
151 % The word matched by (the most recent) ?str search.
152 x-y A range of words; x defaults to 0.
153 * All the arguments, or a null value if there are none.
154 x* Abbreviates `x-$'.
155 x- Like `x*' but omitting word $.
156 Note that a `%' word designator works only when used in one of `!%',
158 `!:%' or `!?str?:%', and only when used after a !? expansion (possibly
159 in an earlier command). Anything else results in an error, although
160 the error may not be the most obvious one.
161 Modifiers
163 After the optional word designator, you can add a sequence of one or
164 more of the following modifiers, each preceded by a `:'. These modi‐
165 fiers also work on the result of filename generation and parameter ex‐
166 pansion, except where noted.
167 a Turn a file name into an absolute path: prepends the current
169 directory, if necessary; remove `.' path segments; and remove
170 `..' path segments and the segments that immediately precede
171 them.
172 This transformation is agnostic about what is in the filesystem,
174 i.e. is on the logical, not the physical directory. It takes
175 place in the same manner as when changing directories when nei‐
176 ther of the options CHASE_DOTS or CHASE_LINKS is set. For exam‐
177 ple, `/before/here/../after' is always transformed to `/be‐
178 fore/after', regardless of whether `/before/here' exists or what
179 kind of object (dir, file, symlink, etc.) it is.
180 A Turn a file name into an absolute path as the `a' modifier does,
182 and then pass the result through the realpath(3) library func‐
183 tion to resolve symbolic links.
184 Note: on systems that do not have a realpath(3) library func‐
186 tion, symbolic links are not resolved, so on those systems `a'
187 and `A' are equivalent.
188 Note: foo:A and realpath(foo) are different on some inputs. For
190 realpath(foo) semantics, see the `P` modifier.
191 c Resolve a command name into an absolute path by searching the
193 command path given by the PATH variable. This does not work for
194 commands containing directory parts. Note also that this does
195 not usually work as a glob qualifier unless a file of the same
196 name is found in the current directory.
197 e Remove all but the part of the filename extension following the
199 `.'; see the definition of the filename extension in the de‐
200 scription of the r modifier below. Note that according to that
201 definition the result will be empty if the string ends with a
202 `.'.
203 h [ digits ]
205 Remove a trailing pathname component, shortening the path by one
206 directory level: this is the `head' of the pathname. This works
207 like `dirname'. If the h is followed immediately (with no spa‐
208 ces or other separator) by any number of decimal digits, and the
209 value of the resulting number is non-zero, that number of lead‐
210 ing components is preserved instead of the final component being
211 removed. In an absolute path the leading `/' is the first com‐
212 ponent, so, for example, if var=/my/path/to/something, then
213 ${var:h3} substitutes /my/path. Consecutive `/'s are treated
214 the same as a single `/'. In parameter substitution, digits may
215 only be used if the expression is in braces, so for example the
216 short form substitution $var:h2 is treated as ${var:h}2, not as
217 ${var:h2}. No restriction applies to the use of digits in his‐
218 tory substitution or globbing qualifiers. If more components
219 are requested than are present, the entire path is substituted
220 (so this does not trigger a `failed modifier' error in history
221 expansion).
222 l Convert the words to all lowercase.
224 p Print the new command but do not execute it. Only works with
226 history expansion.
227 P Turn a file name into an absolute path, like realpath(3). The
229 resulting path will be absolute, have neither `.' nor `..' com‐
230 ponents, and refer to the same directory entry as the input
231 filename.
232 Unlike realpath(3), non-existent trailing components are permit‐
234 ted and preserved.
235 q Quote the substituted words, escaping further substitutions.
237 Works with history expansion and parameter expansion, though for
238 parameters it is only useful if the resulting text is to be
239 re-evaluated such as by eval.
240 Q Remove one level of quotes from the substituted words.
242 r Remove a filename extension leaving the root name. Strings with
244 no filename extension are not altered. A filename extension is
245 a `.' followed by any number of characters (including zero) that
246 are neither `.' nor `/' and that continue to the end of the
247 string. For example, the extension of `foo.orig.c' is `.c', and
248 `dir.c/foo' has no extension.
249 s/l/r[/]
251 Substitute r for l as described below. The substitution is done
252 only for the first string that matches l. For arrays and for
253 filename generation, this applies to each word of the expanded
254 text. See below for further notes on substitutions.
255 The forms `gs/l/r' and `s/l/r/:G' perform global substitution,
257 i.e. substitute every occurrence of r for l. Note that the g or
258 :G must appear in exactly the position shown.
259 See further notes on this form of substitution below.
261 & Repeat the previous s substitution. Like s, may be preceded im‐
263 mediately by a g. In parameter expansion the & must appear in‐
264 side braces, and in filename generation it must be quoted with a
265 backslash.
266 t [ digits ]
268 Remove all leading pathname components, leaving the final compo‐
269 nent (tail). This works like `basename'. Any trailing slashes
270 are first removed. Decimal digits are handled as described
271 above for (h), but in this case that number of trailing compo‐
272 nents is preserved instead of the default 1; 0 is treated the
273 same as 1.
274 u Convert the words to all uppercase.
276 x Like q, but break into words at whitespace. Does not work with
278 parameter expansion.
279 The s/l/r/ substitution works as follows. By default the left-hand
281 side of substitutions are not patterns, but character strings. Any
282 character can be used as the delimiter in place of `/'. A backslash
283 quotes the delimiter character. The character `&', in the
284 right-hand-side r, is replaced by the text from the left-hand-side l.
285 The `&' can be quoted with a backslash. A null l uses the previous
286 string either from the previous l or from the contextual scan string s
287 from `!?s'. You can omit the rightmost delimiter if a newline immedi‐
288 ately follows r; the rightmost `?' in a context scan can similarly be
289 omitted. Note the same record of the last l and r is maintained across
290 all forms of expansion.
291 Note that if a `&' is used within glob qualifiers an extra backslash is
293 needed as a & is a special character in this case.
294 Also note that the order of expansions affects the interpretation of l
296 and r. When used in a history expansion, which occurs before any other
297 expansions, l and r are treated as literal strings (except as explained
298 for HIST_SUBST_PATTERN below). When used in parameter expansion, the
299 replacement of r into the parameter's value is done first, and then any
300 additional process, parameter, command, arithmetic, or brace references
301 are applied, which may evaluate those substitutions and expansions more
302 than once if l appears more than once in the starting value. When used
303 in a glob qualifier, any substitutions or expansions are performed once
304 at the time the qualifier is parsed, even before the `:s' expression
305 itself is divided into l and r sides.
306 If the option HIST_SUBST_PATTERN is set, l is treated as a pattern of
308 the usual form described in the section FILENAME GENERATION below.
309 This can be used in all the places where modifiers are available; note,
310 however, that in globbing qualifiers parameter substitution has already
311 taken place, so parameters in the replacement string should be quoted
312 to ensure they are replaced at the correct time. Note also that com‐
313 plicated patterns used in globbing qualifiers may need the extended
314 glob qualifier notation (#q:s/.../.../) in order for the shell to rec‐
315 ognize the expression as a glob qualifier. Further, note that bad pat‐
316 terns in the substitution are not subject to the NO_BAD_PATTERN option
317 so will cause an error.
318 When HIST_SUBST_PATTERN is set, l may start with a # to indicate that
320 the pattern must match at the start of the string to be substituted,
321 and a % may appear at the start or after an # to indicate that the pat‐
322 tern must match at the end of the string to be substituted. The % or #
323 may be quoted with two backslashes.
324 For example, the following piece of filename generation code with the
326 EXTENDED_GLOB option:
327 print -r -- *.c(#q:s/#%(#b)s(*).c/'S${match[1]}.C'/)
329 takes the expansion of *.c and applies the glob qualifiers in the
331 (#q...) expression, which consists of a substitution modifier anchored
332 to the start and end of each word (#%). This turns on backreferences
333 ((#b)), so that the parenthesised subexpression is available in the re‐
334 placement string as ${match[1]}. The replacement string is quoted so
335 that the parameter is not substituted before the start of filename gen‐
336 eration.
337 The following f, F, w and W modifiers work only with parameter expan‐
339 sion and filename generation. They are listed here to provide a single
340 point of reference for all modifiers.
341 f Repeats the immediately (without a colon) following modifier un‐
343 til the resulting word doesn't change any more.
344 F:expr:
346 Like f, but repeats only n times if the expression expr evalu‐
347 ates to n. Any character can be used instead of the `:'; if
348 `(', `[', or `{' is used as the opening delimiter, the closing
349 delimiter should be ')', `]', or `}', respectively.
350 w Makes the immediately following modifier work on each word in
352 the string.
353 W:sep: Like w but words are considered to be the parts of the string
355 that are separated by sep. Any character can be used instead of
356 the `:'; opening parentheses are handled specially, see above.
357
359 Each part of a command argument that takes the form `<(list)',
360 `>(list)' or `=(list)' is subject to process substitution. The expres‐
361 sion may be preceded or followed by other strings except that, to pre‐
362 vent clashes with commonly occurring strings and patterns, the last
363 form must occur at the start of a command argument, and the forms are
364 only expanded when first parsing command or assignment arguments.
365 Process substitutions may be used following redirection operators; in
366 this case, the substitution must appear with no trailing string.
367 Note that `<<(list)' is not a special syntax; it is equivalent to `<
369 <(list)', redirecting standard input from the result of process substi‐
370 tution. Hence all the following documentation applies. The second
371 form (with the space) is recommended for clarity.
372 In the case of the < or > forms, the shell runs the commands in list as
374 a subprocess of the job executing the shell command line. If the sys‐
375 tem supports the /dev/fd mechanism, the command argument is the name of
376 the device file corresponding to a file descriptor; otherwise, if the
377 system supports named pipes (FIFOs), the command argument will be a
378 named pipe. If the form with > is selected then writing on this spe‐
379 cial file will provide input for list. If < is used, then the file
380 passed as an argument will be connected to the output of the list
381 process. For example,
382 paste <(cut -f1 file1) <(cut -f3 file2) |
384 tee >(process1) >(process2) >/dev/null
385 cuts fields 1 and 3 from the files file1 and file2 respectively, pastes
387 the results together, and sends it to the processes process1 and
388 process2.
389 If =(...) is used instead of <(...), then the file passed as an argu‐
391 ment will be the name of a temporary file containing the output of the
392 list process. This may be used instead of the < form for a program
393 that expects to lseek (see lseek(2)) on the input file.
394 There is an optimisation for substitutions of the form =(<<<arg), where
396 arg is a single-word argument to the here-string redirection <<<. This
397 form produces a file name containing the value of arg after any substi‐
398 tutions have been performed. This is handled entirely within the cur‐
399 rent shell. This is effectively the reverse of the special form
400 $(<arg) which treats arg as a file name and replaces it with the file's
401 contents.
402 The = form is useful as both the /dev/fd and the named pipe implementa‐
404 tion of <(...) have drawbacks. In the former case, some programmes may
405 automatically close the file descriptor in question before examining
406 the file on the command line, particularly if this is necessary for se‐
407 curity reasons such as when the programme is running setuid. In the
408 second case, if the programme does not actually open the file, the sub‐
409 shell attempting to read from or write to the pipe will (in a typical
410 implementation, different operating systems may have different behav‐
411 iour) block for ever and have to be killed explicitly. In both cases,
412 the shell actually supplies the information using a pipe, so that pro‐
413 grammes that expect to lseek (see lseek(2)) on the file will not work.
414 Also note that the previous example can be more compactly and effi‐
416 ciently written (provided the MULTIOS option is set) as:
417 paste <(cut -f1 file1) <(cut -f3 file2) \
419 > >(process1) > >(process2)
420 The shell uses pipes instead of FIFOs to implement the latter two
422 process substitutions in the above example.
423 There is an additional problem with >(process); when this is attached
425 to an external command, the parent shell does not wait for process to
426 finish and hence an immediately following command cannot rely on the
427 results being complete. The problem and solution are the same as de‐
428 scribed in the section MULTIOS in zshmisc(1). Hence in a simplified
429 version of the example above:
430 paste <(cut -f1 file1) <(cut -f3 file2) > >(process)
432 (note that no MULTIOS are involved), process will be run asynchronously
434 as far as the parent shell is concerned. The workaround is:
435 { paste <(cut -f1 file1) <(cut -f3 file2) } > >(process)
437 The extra processes here are spawned from the parent shell which will
439 wait for their completion.
440 Another problem arises any time a job with a substitution that requires
442 a temporary file is disowned by the shell, including the case where
443 `&!' or `&|' appears at the end of a command containing a substitution.
444 In that case the temporary file will not be cleaned up as the shell no
445 longer has any memory of the job. A workaround is to use a subshell,
446 for example,
447 (mycmd =(myoutput)) &!
449 as the forked subshell will wait for the command to finish then remove
451 the temporary file.
452 A general workaround to ensure a process substitution endures for an
454 appropriate length of time is to pass it as a parameter to an anonymous
455 shell function (a piece of shell code that is run immediately with
456 function scope). For example, this code:
457 () {
459 print File $1:
460 cat $1
461 } =(print This be the verse)
462 outputs something resembling the following
464 File /tmp/zsh6nU0kS:
466 This be the verse
467 The temporary file created by the process substitution will be deleted
469 when the function exits.
470
472 The character `$' is used to introduce parameter expansions. See zsh‐
473 param(1) for a description of parameters, including arrays, associative
474 arrays, and subscript notation to access individual array elements.
475 Note in particular the fact that words of unquoted parameters are not
477 automatically split on whitespace unless the option SH_WORD_SPLIT is
478 set; see references to this option below for more details. This is an
479 important difference from other shells. However, as in other shells,
480 null words are elided from unquoted parameters' expansions.
481 With default options, after the assignments:
483 array=("first word" "" "third word")
485 scalar="only word"
486 then $array substitutes two words, `first word' and `third word', and
488 $scalar substitutes a single word `only word'. Note that second ele‐
489 ment of array was elided. Scalar parameters can be elided too if their
490 value is null (empty). To avoid elision, use quoting as follows:
491 "$scalar" for scalars and "${array[@]}" or "${(@)array}" for arrays.
492 (The last two forms are equivalent.)
493 Parameter expansions can involve flags, as in `${(@kv)aliases}', and
495 other operators, such as `${PREFIX:-"/usr/local"}'. Parameter expan‐
496 sions can also be nested. These topics will be introduced below. The
497 full rules are complicated and are noted at the end.
498 In the expansions discussed below that require a pattern, the form of
500 the pattern is the same as that used for filename generation; see the
501 section `Filename Generation'. Note that these patterns, along with
502 the replacement text of any substitutions, are themselves subject to
503 parameter expansion, command substitution, and arithmetic expansion.
504 In addition to the following operations, the colon modifiers described
505 in the section `Modifiers' in the section `History Expansion' can be
506 applied: for example, ${i:s/foo/bar/} performs string substitution on
507 the expansion of parameter $i.
508 In the following descriptions, `word' refers to a single word substi‐
510 tuted on the command line, not necessarily a space delimited word.
511 ${name}
513 The value, if any, of the parameter name is substituted. The
514 braces are required if the expansion is to be followed by a let‐
515 ter, digit, or underscore that is not to be interpreted as part
516 of name. In addition, more complicated forms of substitution
517 usually require the braces to be present; exceptions, which only
518 apply if the option KSH_ARRAYS is not set, are a single sub‐
519 script or any colon modifiers appearing after the name, or any
520 of the characters `^', `=', `~', `#' or `+' appearing before the
521 name, all of which work with or without braces.
522 If name is an array parameter, and the KSH_ARRAYS option is not
524 set, then the value of each element of name is substituted, one
525 element per word. Otherwise, the expansion results in one word
526 only; with KSH_ARRAYS, this is the first element of an array.
527 No field splitting is done on the result unless the
528 SH_WORD_SPLIT option is set. See also the flags = and
529 s:string:.
530 ${+name}
532 If name is the name of a set parameter `1' is substituted, oth‐
533 erwise `0' is substituted.
534 ${name-word}
536 ${name:-word}
537 If name is set, or in the second form is non-null, then substi‐
538 tute its value; otherwise substitute word. In the second form
539 name may be omitted, in which case word is always substituted.
540 ${name+word}
542 ${name:+word}
543 If name is set, or in the second form is non-null, then substi‐
544 tute word; otherwise substitute nothing.
545 ${name=word}
547 ${name:=word}
548 ${name::=word}
549 In the first form, if name is unset then set it to word; in the
550 second form, if name is unset or null then set it to word; and
551 in the third form, unconditionally set name to word. In all
552 forms, the value of the parameter is then substituted.
553 ${name?word}
555 ${name:?word}
556 In the first form, if name is set, or in the second form if name
557 is both set and non-null, then substitute its value; otherwise,
558 print word and exit from the shell. Interactive shells instead
559 return to the prompt. If word is omitted, then a standard mes‐
560 sage is printed.
561 In any of the above expressions that test a variable and substitute an
563 alternate word, note that you can use standard shell quoting in the
564 word value to selectively override the splitting done by the
565 SH_WORD_SPLIT option and the = flag, but not splitting by the s:string:
566 flag.
567 In the following expressions, when name is an array and the substitu‐
569 tion is not quoted, or if the `(@)' flag or the name[@] syntax is used,
570 matching and replacement is performed on each array element separately.
571 ${name#pattern}
573 ${name##pattern}
574 If the pattern matches the beginning of the value of name, then
575 substitute the value of name with the matched portion deleted;
576 otherwise, just substitute the value of name. In the first
577 form, the smallest matching pattern is preferred; in the second
578 form, the largest matching pattern is preferred.
579 ${name%pattern}
581 ${name%%pattern}
582 If the pattern matches the end of the value of name, then sub‐
583 stitute the value of name with the matched portion deleted; oth‐
584 erwise, just substitute the value of name. In the first form,
585 the smallest matching pattern is preferred; in the second form,
586 the largest matching pattern is preferred.
587 ${name:#pattern}
589 If the pattern matches the value of name, then substitute the
590 empty string; otherwise, just substitute the value of name. If
591 name is an array the matching array elements are removed (use
592 the `(M)' flag to remove the non-matched elements).
593 ${name:|arrayname}
595 If arrayname is the name (N.B., not contents) of an array vari‐
596 able, then any elements contained in arrayname are removed from
597 the substitution of name. If the substitution is scalar, either
598 because name is a scalar variable or the expression is quoted,
599 the elements of arrayname are instead tested against the entire
600 expression.
601 ${name:*arrayname}
603 Similar to the preceding substitution, but in the opposite
604 sense, so that entries present in both the original substitution
605 and as elements of arrayname are retained and others removed.
606 ${name:^arrayname}
608 ${name:^^arrayname}
609 Zips two arrays, such that the output array is twice as long as
610 the shortest (longest for `:^^') of name and arrayname, with the
611 elements alternatingly being picked from them. For `:^', if one
612 of the input arrays is longer, the output will stop when the end
613 of the shorter array is reached. Thus,
614 a=(1 2 3 4); b=(a b); print ${a:^b}
616 will output `1 a 2 b'. For `:^^', then the input is repeated
618 until all of the longer array has been used up and the above
619 will output `1 a 2 b 3 a 4 b'.
620 Either or both inputs may be a scalar, they will be treated as
622 an array of length 1 with the scalar as the only element. If ei‐
623 ther array is empty, the other array is output with no extra el‐
624 ements inserted.
625 Currently the following code will output `a b' and `1' as two
627 separate elements, which can be unexpected. The second print
628 provides a workaround which should continue to work if this is
629 changed.
630 a=(a b); b=(1 2); print -l "${a:^b}"; print -l "${${a:^b}}"
632 ${name:offset}
634 ${name:offset:length}
635 This syntax gives effects similar to parameter subscripting in
636 the form $name[start,end], but is compatible with other shells;
637 note that both offset and length are interpreted differently
638 from the components of a subscript.
639 If offset is non-negative, then if the variable name is a scalar
641 substitute the contents starting offset characters from the
642 first character of the string, and if name is an array substi‐
643 tute elements starting offset elements from the first element.
644 If length is given, substitute that many characters or elements,
645 otherwise the entire rest of the scalar or array.
646 A positive offset is always treated as the offset of a character
648 or element in name from the first character or element of the
649 array (this is different from native zsh subscript notation).
650 Hence 0 refers to the first character or element regardless of
651 the setting of the option KSH_ARRAYS.
652 A negative offset counts backwards from the end of the scalar or
654 array, so that -1 corresponds to the last character or element,
655 and so on.
656 When positive, length counts from the offset position toward the
658 end of the scalar or array. When negative, length counts back
659 from the end. If this results in a position smaller than off‐
660 set, a diagnostic is printed and nothing is substituted.
661 The option MULTIBYTE is obeyed, i.e. the offset and length count
663 multibyte characters where appropriate.
664 offset and length undergo the same set of shell substitutions as
666 for scalar assignment; in addition, they are then subject to
667 arithmetic evaluation. Hence, for example
668 print ${foo:3}
670 print ${foo: 1 + 2}
671 print ${foo:$(( 1 + 2))}
672 print ${foo:$(echo 1 + 2)}
673 all have the same effect, extracting the string starting at the
675 fourth character of $foo if the substitution would otherwise re‐
676 turn a scalar, or the array starting at the fourth element if
677 $foo would return an array. Note that with the option KSH_AR‐
678 RAYS $foo always returns a scalar (regardless of the use of the
679 offset syntax) and a form such as ${foo[*]:3} is required to ex‐
680 tract elements of an array named foo.
681 If offset is negative, the - may not appear immediately after
683 the : as this indicates the ${name:-word} form of substitution.
684 Instead, a space may be inserted before the -. Furthermore,
685 neither offset nor length may begin with an alphabetic character
686 or & as these are used to indicate history-style modifiers. To
687 substitute a value from a variable, the recommended approach is
688 to precede it with a $ as this signifies the intention (parame‐
689 ter substitution can easily be rendered unreadable); however, as
690 arithmetic substitution is performed, the expression ${var:
691 offs} does work, retrieving the offset from $offs.
692 For further compatibility with other shells there is a special
694 case for array offset 0. This usually accesses the first ele‐
695 ment of the array. However, if the substitution refers to the
696 positional parameter array, e.g. $@ or $*, then offset 0 instead
697 refers to $0, offset 1 refers to $1, and so on. In other words,
698 the positional parameter array is effectively extended by
699 prepending $0. Hence ${*:0:1} substitutes $0 and ${*:1:1} sub‐
700 stitutes $1.
701 ${name/pattern/repl}
703 ${name//pattern/repl}
704 ${name:/pattern/repl}
705 Replace the longest possible match of pattern in the expansion
706 of parameter name by string repl. The first form replaces just
707 the first occurrence, the second form all occurrences, and the
708 third form replaces only if pattern matches the entire string.
709 Both pattern and repl are subject to double-quoted substitution,
710 so that expressions like ${name/$opat/$npat} will work, but obey
711 the usual rule that pattern characters in $opat are not treated
712 specially unless either the option GLOB_SUBST is set, or $opat
713 is instead substituted as ${~opat}.
714 The pattern may begin with a `#', in which case the pattern must
716 match at the start of the string, or `%', in which case it must
717 match at the end of the string, or `#%' in which case the pat‐
718 tern must match the entire string. The repl may be an empty
719 string, in which case the final `/' may also be omitted. To
720 quote the final `/' in other cases it should be preceded by a
721 single backslash; this is not necessary if the `/' occurs inside
722 a substituted parameter. Note also that the `#', `%' and `#%
723 are not active if they occur inside a substituted parameter,
724 even at the start.
725 If, after quoting rules apply, ${name} expands to an array, the
727 replacements act on each element individually. Note also the
728 effect of the I and S parameter expansion flags below; however,
729 the flags M, R, B, E and N are not useful.
730 For example,
732 foo="twinkle twinkle little star" sub="t*e" rep="spy"
734 print ${foo//${~sub}/$rep}
735 print ${(S)foo//${~sub}/$rep}
736 Here, the `~' ensures that the text of $sub is treated as a pat‐
738 tern rather than a plain string. In the first case, the longest
739 match for t*e is substituted and the result is `spy star', while
740 in the second case, the shortest matches are taken and the re‐
741 sult is `spy spy lispy star'.
742 ${#spec}
744 If spec is one of the above substitutions, substitute the length
745 in characters of the result instead of the result itself. If
746 spec is an array expression, substitute the number of elements
747 of the result. This has the side-effect that joining is skipped
748 even in quoted forms, which may affect other sub-expressions in
749 spec. Note that `^', `=', and `~', below, must appear to the
750 left of `#' when these forms are combined.
751 If the option POSIX_IDENTIFIERS is not set, and spec is a simple
753 name, then the braces are optional; this is true even for spe‐
754 cial parameters so e.g. $#- and $#* take the length of the
755 string $- and the array $* respectively. If POSIX_IDENTIFIERS
756 is set, then braces are required for the # to be treated in this
757 fashion.
758 ${^spec}
760 Turn on the RC_EXPAND_PARAM option for the evaluation of spec;
761 if the `^' is doubled, turn it off. When this option is set,
762 array expansions of the form foo${xx}bar, where the parameter xx
763 is set to (a b c), are substituted with `fooabar foobbar
764 foocbar' instead of the default `fooa b cbar'. Note that an
765 empty array will therefore cause all arguments to be removed.
766 Internally, each such expansion is converted into the equivalent
768 list for brace expansion. E.g., ${^var} becomes
769 {$var[1],$var[2],...}, and is processed as described in the sec‐
770 tion `Brace Expansion' below: note, however, the expansion hap‐
771 pens immediately, with any explicit brace expansion happening
772 later. If word splitting is also in effect the $var[N] may
773 themselves be split into different list elements.
774 ${=spec}
776 Perform word splitting using the rules for SH_WORD_SPLIT during
777 the evaluation of spec, but regardless of whether the parameter
778 appears in double quotes; if the `=' is doubled, turn it off.
779 This forces parameter expansions to be split into separate words
780 before substitution, using IFS as a delimiter. This is done by
781 default in most other shells.
782 Note that splitting is applied to word in the assignment forms
784 of spec before the assignment to name is performed. This af‐
785 fects the result of array assignments with the A flag.
786 ${~spec}
788 Turn on the GLOB_SUBST option for the evaluation of spec; if the
789 `~' is doubled, turn it off. When this option is set, the
790 string resulting from the expansion will be interpreted as a
791 pattern anywhere that is possible, such as in filename expansion
792 and filename generation and pattern-matching contexts like the
793 right hand side of the `=' and `!=' operators in conditions.
794 In nested substitutions, note that the effect of the ~ applies
796 to the result of the current level of substitution. A surround‐
797 ing pattern operation on the result may cancel it. Hence, for
798 example, if the parameter foo is set to *, ${~foo//\*/*.c} is
799 substituted by the pattern *.c, which may be expanded by file‐
800 name generation, but ${${~foo}//\*/*.c} substitutes to the
801 string *.c, which will not be further expanded.
802 If a ${...} type parameter expression or a $(...) type command substi‐
804 tution is used in place of name above, it is expanded first and the re‐
805 sult is used as if it were the value of name. Thus it is possible to
806 perform nested operations: ${${foo#head}%tail} substitutes the value
807 of $foo with both `head' and `tail' deleted. The form with $(...) is
808 often useful in combination with the flags described next; see the ex‐
809 amples below. Each name or nested ${...} in a parameter expansion may
810 also be followed by a subscript expression as described in Array Param‐
811 eters in zshparam(1).
812 Note that double quotes may appear around nested expressions, in which
814 case only the part inside is treated as quoted; for example,
815 ${(f)"$(foo)"} quotes the result of $(foo), but the flag `(f)' (see be‐
816 low) is applied using the rules for unquoted expansions. Note further
817 that quotes are themselves nested in this context; for example, in
818 "${(@f)"$(foo)"}", there are two sets of quotes, one surrounding the
819 whole expression, the other (redundant) surrounding the $(foo) as be‐
820 fore.
821 Parameter Expansion Flags
823 If the opening brace is directly followed by an opening parenthesis,
824 the string up to the matching closing parenthesis will be taken as a
825 list of flags. In cases where repeating a flag is meaningful, the rep‐
826 etitions need not be consecutive; for example, `(q%q%q)' means the same
827 thing as the more readable `(%%qqq)'. The following flags are sup‐
828 ported:
829 # Evaluate the resulting words as numeric expressions and output
831 the characters corresponding to the resulting integer. Note
832 that this form is entirely distinct from use of the # without
833 parentheses.
834 If the MULTIBYTE option is set and the number is greater than
836 127 (i.e. not an ASCII character) it is treated as a Unicode
837 character.
838 % Expand all % escapes in the resulting words in the same way as
840 in prompts (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)). If
841 this flag is given twice, full prompt expansion is done on the
842 resulting words, depending on the setting of the PROMPT_PERCENT,
843 PROMPT_SUBST and PROMPT_BANG options.
844 @ In double quotes, array elements are put into separate words.
846 E.g., `"${(@)foo}"' is equivalent to `"${foo[@]}"' and
847 `"${(@)foo[1,2]}"' is the same as `"$foo[1]" "$foo[2]"'. This
848 is distinct from field splitting by the f, s or z flags, which
849 still applies within each array element.
850 A Convert the substitution into an array expression, even if it
852 otherwise would be scalar. This has lower precedence than sub‐
853 scripting, so one level of nested expansion is required in order
854 that subscripts apply to array elements. Thus ${${(A)name}[1]}
855 yields the full value of name when name is scalar.
856 This assigns an array parameter with `${...=...}', `${...:=...}'
858 or `${...::=...}'. If this flag is repeated (as in `AA'), as‐
859 signs an associative array parameter. Assignment is made before
860 sorting or padding; if field splitting is active, the word part
861 is split before assignment. The name part may be a subscripted
862 range for ordinary arrays; when assigning an associative array,
863 the word part must be converted to an array, for example by us‐
864 ing `${(AA)=name=...}' to activate field splitting.
865 Surrounding context such as additional nesting or use of the
867 value in a scalar assignment may cause the array to be joined
868 back into a single string again.
869 a Sort in array index order; when combined with `O' sort in re‐
871 verse array index order. Note that `a' is therefore equivalent
872 to the default but `Oa' is useful for obtaining an array's ele‐
873 ments in reverse order.
874 b Quote with backslashes only characters that are special to pat‐
876 tern matching. This is useful when the contents of the variable
877 are to be tested using GLOB_SUBST, including the ${~...} switch.
878 Quoting using one of the q family of flags does not work for
880 this purpose since quotes are not stripped from non-pattern
881 characters by GLOB_SUBST. In other words,
882 pattern=${(q)str}
884 [[ $str = ${~pattern} ]]
885 works if $str is `a*b' but not if it is `a b', whereas
887 pattern=${(b)str}
889 [[ $str = ${~pattern} ]]
890 is always true for any possible value of $str.
892 c With ${#name}, count the total number of characters in an array,
894 as if the elements were concatenated with spaces between them.
895 This is not a true join of the array, so other expressions used
896 with this flag may have an effect on the elements of the array
897 before it is counted.
898 C Capitalize the resulting words. `Words' in this case refers to
900 sequences of alphanumeric characters separated by non-alphanu‐
901 merics, not to words that result from field splitting.
902 D Assume the string or array elements contain directories and at‐
904 tempt to substitute the leading part of these by names. The re‐
905 mainder of the path (the whole of it if the leading part was not
906 substituted) is then quoted so that the whole string can be used
907 as a shell argument. This is the reverse of `~' substitution:
908 see the section FILENAME EXPANSION below.
909 e Perform single word shell expansions, namely parameter expan‐
911 sion, command substitution and arithmetic expansion, on the re‐
912 sult. Such expansions can be nested but too deep recursion may
913 have unpredictable effects.
914 f Split the result of the expansion at newlines. This is a short‐
916 hand for `ps:\n:'.
917 F Join the words of arrays together using newline as a separator.
919 This is a shorthand for `pj:\n:'.
920 g:opts:
922 Process escape sequences like the echo builtin when no options
923 are given (g::). With the o option, octal escapes don't take a
924 leading zero. With the c option, sequences like `^X' are also
925 processed. With the e option, processes `\M-t' and similar se‐
926 quences like the print builtin. With both of the o and e op‐
927 tions, behaves like the print builtin except that in none of
928 these modes is `\c' interpreted.
929 i Sort case-insensitively. May be combined with `n' or `O'.
931 k If name refers to an associative array, substitute the keys (el‐
933 ement names) rather than the values of the elements. Used with
934 subscripts (including ordinary arrays), force indices or keys to
935 be substituted even if the subscript form refers to values.
936 However, this flag may not be combined with subscript ranges.
937 With the KSH_ARRAYS option a subscript `[*]' or `[@]' is needed
938 to operate on the whole array, as usual.
939 L Convert all letters in the result to lower case.
941 n Sort decimal integers numerically; if the first differing char‐
943 acters of two test strings are not digits, sorting is lexical.
944 Integers with more initial zeroes are sorted before those with
945 fewer or none. Hence the array `foo1 foo02 foo2 foo3 foo20
946 foo23' is sorted into the order shown. May be combined with `i'
947 or `O'.
948 o Sort the resulting words in ascending order; if this appears on
950 its own the sorting is lexical and case-sensitive (unless the
951 locale renders it case-insensitive). Sorting in ascending order
952 is the default for other forms of sorting, so this is ignored if
953 combined with `a', `i' or `n'.
954 O Sort the resulting words in descending order; `O' without `a',
956 `i' or `n' sorts in reverse lexical order. May be combined with
957 `a', `i' or `n' to reverse the order of sorting.
958 P This forces the value of the parameter name to be interpreted as
960 a further parameter name, whose value will be used where appro‐
961 priate. Note that flags set with one of the typeset family of
962 commands (in particular case transformations) are not applied to
963 the value of name used in this fashion.
964 If used with a nested parameter or command substitution, the re‐
966 sult of that will be taken as a parameter name in the same way.
967 For example, if you have `foo=bar' and `bar=baz', the strings
968 ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be expanded
969 to `baz'.
970 Likewise, if the reference is itself nested, the expression with
972 the flag is treated as if it were directly replaced by the pa‐
973 rameter name. It is an error if this nested substitution pro‐
974 duces an array with more than one word. For example, if
975 `name=assoc' where the parameter assoc is an associative array,
976 then `${${(P)name}[elt]}' refers to the element of the associa‐
977 tive subscripted `elt'.
978 q Quote characters that are special to the shell in the resulting
980 words with backslashes; unprintable or invalid characters are
981 quoted using the $'\NNN' form, with separate quotes for each
982 octet.
983 If this flag is given twice, the resulting words are quoted in
985 single quotes and if it is given three times, the words are
986 quoted in double quotes; in these forms no special handling of
987 unprintable or invalid characters is attempted. If the flag is
988 given four times, the words are quoted in single quotes preceded
989 by a $. Note that in all three of these forms quoting is done
990 unconditionally, even if this does not change the way the re‐
991 sulting string would be interpreted by the shell.
992 If a q- is given (only a single q may appear), a minimal form of
994 single quoting is used that only quotes the string if needed to
995 protect special characters. Typically this form gives the most
996 readable output.
997 If a q+ is given, an extended form of minimal quoting is used
999 that causes unprintable characters to be rendered using $'...'.
1000 This quoting is similar to that used by the output of values by
1001 the typeset family of commands.
1002 Q Remove one level of quotes from the resulting words.
1004 t Use a string describing the type of the parameter where the
1006 value of the parameter would usually appear. This string con‐
1007 sists of keywords separated by hyphens (`-'). The first keyword
1008 in the string describes the main type, it can be one of
1009 `scalar', `array', `integer', `float' or `association'. The
1010 other keywords describe the type in more detail:
1011 local for local parameters
1013 left for left justified parameters
1015 right_blanks
1017 for right justified parameters with leading blanks
1018 right_zeros
1020 for right justified parameters with leading zeros
1021 lower for parameters whose value is converted to all lower case
1023 when it is expanded
1024 upper for parameters whose value is converted to all upper case
1026 when it is expanded
1027 readonly
1029 for readonly parameters
1030 tag for tagged parameters
1032 export for exported parameters
1034 unique for arrays which keep only the first occurrence of dupli‐
1036 cated values
1037 hide for parameters with the `hide' flag
1039 hideval
1041 for parameters with the `hideval' flag
1042 special
1044 for special parameters defined by the shell
1045 u Expand only the first occurrence of each unique word.
1047 U Convert all letters in the result to upper case.
1049 v Used with k, substitute (as two consecutive words) both the key
1051 and the value of each associative array element. Used with sub‐
1052 scripts, force values to be substituted even if the subscript
1053 form refers to indices or keys.
1054 V Make any special characters in the resulting words visible.
1056 w With ${#name}, count words in arrays or strings; the s flag may
1058 be used to set a word delimiter.
1059 W Similar to w with the difference that empty words between re‐
1061 peated delimiters are also counted.
1062 X With this flag, parsing errors occurring with the Q, e and #
1064 flags or the pattern matching forms such as `${name#pattern}'
1065 are reported. Without the flag, errors are silently ignored.
1066 z Split the result of the expansion into words using shell parsing
1068 to find the words, i.e. taking into account any quoting in the
1069 value. Comments are not treated specially but as ordinary
1070 strings, similar to interactive shells with the INTERACTIVE_COM‐
1071 MENTS option unset (however, see the Z flag below for related
1072 options)
1073 Note that this is done very late, even later than the `(s)'
1075 flag. So to access single words in the result use nested expan‐
1076 sions as in `${${(z)foo}[2]}'. Likewise, to remove the quotes in
1077 the resulting words use `${(Q)${(z)foo}}'.
1078 0 Split the result of the expansion on null bytes. This is a
1080 shorthand for `ps:\0:'.
1081 The following flags (except p) are followed by one or more arguments as
1083 shown. Any character, or the matching pairs `(...)', `{...}', `[...]',
1084 or `<...>', may be used in place of a colon as delimiters, but note
1085 that when a flag takes more than one argument, a matched pair of delim‐
1086 iters must surround each argument.
1087 p Recognize the same escape sequences as the print builtin in
1089 string arguments to any of the flags described below that follow
1090 this argument.
1091 Alternatively, with this option string arguments may be in the
1093 form $var in which case the value of the variable is substi‐
1094 tuted. Note this form is strict; the string argument does not
1095 undergo general parameter expansion.
1096 For example,
1098 sep=:
1100 val=a:b:c
1101 print ${(ps.$sep.)val}
1102 splits the variable on a :.
1104 ~ Strings inserted into the expansion by any of the flags below
1106 are to be treated as patterns. This applies to the string argu‐
1107 ments of flags that follow ~ within the same set of parentheses.
1108 Compare with ~ outside parentheses, which forces the entire sub‐
1109 stituted string to be treated as a pattern. Hence, for example,
1110 [[ "?" = ${(~j.|.)array} ]]
1112 treats `|' as a pattern and succeeds if and only if $array con‐
1114 tains the string `?' as an element. The ~ may be repeated to
1115 toggle the behaviour; its effect only lasts to the end of the
1116 parenthesised group.
1117 j:string:
1119 Join the words of arrays together using string as a separator.
1120 Note that this occurs before field splitting by the s:string:
1121 flag or the SH_WORD_SPLIT option.
1122 l:expr::string1::string2:
1124 Pad the resulting words on the left. Each word will be trun‐
1125 cated if required and placed in a field expr characters wide.
1126 The arguments :string1: and :string2: are optional; neither, the
1128 first, or both may be given. Note that the same pairs of delim‐
1129 iters must be used for each of the three arguments. The space
1130 to the left will be filled with string1 (concatenated as often
1131 as needed) or spaces if string1 is not given. If both string1
1132 and string2 are given, string2 is inserted once directly to the
1133 left of each word, truncated if necessary, before string1 is
1134 used to produce any remaining padding.
1135 If either of string1 or string2 is present but empty, i.e. there
1137 are two delimiters together at that point, the first character
1138 of $IFS is used instead.
1139 If the MULTIBYTE option is in effect, the flag m may also be
1141 given, in which case widths will be used for the calculation of
1142 padding; otherwise individual multibyte characters are treated
1143 as occupying one unit of width.
1144 If the MULTIBYTE option is not in effect, each byte in the
1146 string is treated as occupying one unit of width.
1147 Control characters are always assumed to be one unit wide; this
1149 allows the mechanism to be used for generating repetitions of
1150 control characters.
1151 m Only useful together with one of the flags l or r or with the #
1153 length operator when the MULTIBYTE option is in effect. Use the
1154 character width reported by the system in calculating how much
1155 of the string it occupies or the overall length of the string.
1156 Most printable characters have a width of one unit, however cer‐
1157 tain Asian character sets and certain special effects use wider
1158 characters; combining characters have zero width. Non-printable
1159 characters are arbitrarily counted as zero width; how they would
1160 actually be displayed will vary.
1161 If the m is repeated, the character either counts zero (if it
1163 has zero width), else one. For printable character strings this
1164 has the effect of counting the number of glyphs (visibly sepa‐
1165 rate characters), except for the case where combining characters
1166 themselves have non-zero width (true in certain alphabets).
1167 r:expr::string1::string2:
1169 As l, but pad the words on the right and insert string2 immedi‐
1170 ately to the right of the string to be padded.
1171 Left and right padding may be used together. In this case the
1173 strategy is to apply left padding to the first half width of
1174 each of the resulting words, and right padding to the second
1175 half. If the string to be padded has odd width the extra pad‐
1176 ding is applied on the left.
1177 s:string:
1179 Force field splitting at the separator string. Note that a
1180 string of two or more characters means that all of them must
1181 match in sequence; this differs from the treatment of two or
1182 more characters in the IFS parameter. See also the = flag and
1183 the SH_WORD_SPLIT option. An empty string may also be given in
1184 which case every character will be a separate element.
1185 For historical reasons, the usual behaviour that empty array el‐
1187 ements are retained inside double quotes is disabled for arrays
1188 generated by splitting; hence the following:
1189 line="one::three"
1191 print -l "${(s.:.)line}"
1192 produces two lines of output for one and three and elides the
1194 empty field. To override this behaviour, supply the `(@)' flag
1195 as well, i.e. "${(@s.:.)line}".
1196 Z:opts:
1198 As z but takes a combination of option letters between a follow‐
1199 ing pair of delimiter characters. With no options the effect is
1200 identical to z. (Z+c+) causes comments to be parsed as a string
1201 and retained; any field in the resulting array beginning with an
1202 unquoted comment character is a comment. (Z+C+) causes comments
1203 to be parsed and removed. The rule for comments is standard:
1204 anything between a word starting with the third character of
1205 $HISTCHARS, default #, up to the next newline is a comment.
1206 (Z+n+) causes unquoted newlines to be treated as ordinary white‐
1207 space, else they are treated as if they are shell code delim‐
1208 iters and converted to semicolons. Options are combined within
1209 the same set of delimiters, e.g. (Z+Cn+).
1210 _:flags:
1212 The underscore (_) flag is reserved for future use. As of this
1213 revision of zsh, there are no valid flags; anything following an
1214 underscore, other than an empty pair of delimiters, is treated
1215 as an error, and the flag itself has no effect.
1216 The following flags are meaningful with the ${...#...} or ${...%...}
1218 forms. The S and I flags may also be used with the ${.../...} forms.
1219 S With # or ##, search for the match that starts closest to the
1221 start of the string (a `substring match'). Of all matches at a
1222 particular position, # selects the shortest and ## the longest:
1223 % str="aXbXc"
1225 % echo ${(S)str#X*}
1226 abXc
1227 % echo ${(S)str##X*}
1228 a
1229 %
1230 With % or %%, search for the match that starts closest to the
1232 end of the string:
1233 % str="aXbXc"
1235 % echo ${(S)str%X*}
1236 aXbc
1237 % echo ${(S)str%%X*}
1238 aXb
1239 %
1240 (Note that % and %% don't search for the match that ends closest
1242 to the end of the string, as one might expect.)
1243 With substitution via ${.../...} or ${...//...}, specifies
1245 non-greedy matching, i.e. that the shortest instead of the long‐
1246 est match should be replaced:
1247 % str="abab"
1249 % echo ${str/*b/_}
1250 _
1251 % echo ${(S)str/*b/_}
1252 _ab
1253 %
1254 I:expr:
1256 Search the exprth match (where expr evaluates to a number).
1257 This only applies when searching for substrings, either with the
1258 S flag, or with ${.../...} (only the exprth match is substi‐
1259 tuted) or ${...//...} (all matches from the exprth on are sub‐
1260 stituted). The default is to take the first match.
1261 The exprth match is counted such that there is either one or
1263 zero matches from each starting position in the string, although
1264 for global substitution matches overlapping previous replace‐
1265 ments are ignored. With the ${...%...} and ${...%%...} forms,
1266 the starting position for the match moves backwards from the end
1267 as the index increases, while with the other forms it moves for‐
1268 ward from the start.
1269 Hence with the string
1271 which switch is the right switch for Ipswich?
1272 substitutions of the form ${(SI:N:)string#w*ch} as N increases
1273 from 1 will match and remove `which', `witch', `witch' and
1274 `wich'; the form using `##' will match and remove `which switch
1275 is the right switch for Ipswich', `witch is the right switch for
1276 Ipswich', `witch for Ipswich' and `wich'. The form using `%'
1277 will remove the same matches as for `#', but in reverse order,
1278 and the form using `%%' will remove the same matches as for `##'
1279 in reverse order.
1280 B Include the index of the beginning of the match in the result.
1282 E Include the index one character past the end of the match in the
1284 result (note this is inconsistent with other uses of parameter
1285 index).
1286 M Include the matched portion in the result.
1288 N Include the length of the match in the result.
1290 R Include the unmatched portion in the result (the Rest).
1292 Rules
1294 Here is a summary of the rules for substitution; this assumes that
1295 braces are present around the substitution, i.e. ${...}. Some particu‐
1296 lar examples are given below. Note that the Zsh Development Group ac‐
1297 cepts no responsibility for any brain damage which may occur during the
1298 reading of the following rules.
1299 1. Nested substitution
1301 If multiple nested ${...} forms are present, substitution is
1302 performed from the inside outwards. At each level, the substi‐
1303 tution takes account of whether the current value is a scalar or
1304 an array, whether the whole substitution is in double quotes,
1305 and what flags are supplied to the current level of substitu‐
1306 tion, just as if the nested substitution were the outermost.
1307 The flags are not propagated up to enclosing substitutions; the
1308 nested substitution will return either a scalar or an array as
1309 determined by the flags, possibly adjusted for quoting. All the
1310 following steps take place where applicable at all levels of
1311 substitution.
1312 Note that, unless the `(P)' flag is present, the flags and any
1314 subscripts apply directly to the value of the nested substitu‐
1315 tion; for example, the expansion ${${foo}} behaves exactly the
1316 same as ${foo}. When the `(P)' flag is present in a nested sub‐
1317 stitution, the other substitution rules are applied to the value
1318 before it is interpreted as a name, so ${${(P)foo}} may differ
1319 from ${(P)foo}.
1320 At each nested level of substitution, the substituted words un‐
1322 dergo all forms of single-word substitution (i.e. not filename
1323 generation), including command substitution, arithmetic expan‐
1324 sion and filename expansion (i.e. leading ~ and =). Thus, for
1325 example, ${${:-=cat}:h} expands to the directory where the cat
1326 program resides. (Explanation: the internal substitution has no
1327 parameter but a default value =cat, which is expanded by file‐
1328 name expansion to a full path; the outer substitution then ap‐
1329 plies the modifier :h and takes the directory part of the path.)
1330 2. Internal parameter flags
1332 Any parameter flags set by one of the typeset family of com‐
1333 mands, in particular the -L, -R, -Z, -u and -l options for pad‐
1334 ding and capitalization, are applied directly to the parameter
1335 value. Note these flags are options to the command, e.g. `type‐
1336 set -Z'; they are not the same as the flags used within parame‐
1337 ter substitutions.
1338 At the outermost level of substitution, the `(P)' flag (rule 4.)
1340 ignores these transformations and uses the unmodified value of
1341 the parameter as the name to be replaced. This is usually the
1342 desired behavior because padding may make the value syntacti‐
1343 cally illegal as a parameter name, but if capitalization changes
1344 are desired, use the ${${(P)foo}} form (rule 25.).
1345 3. Parameter subscripting
1347 If the value is a raw parameter reference with a subscript, such
1348 as ${var[3]}, the effect of subscripting is applied directly to
1349 the parameter. Subscripts are evaluated left to right; subse‐
1350 quent subscripts apply to the scalar or array value yielded by
1351 the previous subscript. Thus if var is an array, ${var[1][2]}
1352 is the second character of the first word, but ${var[2,4][2]} is
1353 the entire third word (the second word of the range of words two
1354 through four of the original array). Any number of subscripts
1355 may appear. Flags such as `(k)' and `(v)' which alter the re‐
1356 sult of subscripting are applied.
1357 4. Parameter name replacement
1359 At the outermost level of nesting only, the `(P)' flag is ap‐
1360 plied. This treats the value so far as a parameter name (which
1361 may include a subscript expression) and replaces that with the
1362 corresponding value. This replacement occurs later if the `(P)'
1363 flag appears in a nested substitution.
1364 If the value so far names a parameter that has internal flags
1366 (rule 2.), those internal flags are applied to the new value af‐
1367 ter replacement.
1368 5. Double-quoted joining
1370 If the value after this process is an array, and the substitu‐
1371 tion appears in double quotes, and neither an `(@)' flag nor a
1372 `#' length operator is present at the current level, then words
1373 of the value are joined with the first character of the parame‐
1374 ter $IFS, by default a space, between each word (single word ar‐
1375 rays are not modified). If the `(j)' flag is present, that is
1376 used for joining instead of $IFS.
1377 6. Nested subscripting
1379 Any remaining subscripts (i.e. of a nested substitution) are
1380 evaluated at this point, based on whether the value is an array
1381 or a scalar. As with 3., multiple subscripts can appear. Note
1382 that ${foo[2,4][2]} is thus equivalent to ${${foo[2,4]}[2]} and
1383 also to "${${(@)foo[2,4]}[2]}" (the nested substitution returns
1384 an array in both cases), but not to "${${foo[2,4]}[2]}" (the
1385 nested substitution returns a scalar because of the quotes).
1386 7. Modifiers
1388 Any modifiers, as specified by a trailing `#', `%', `/' (possi‐
1389 bly doubled) or by a set of modifiers of the form `:...' (see
1390 the section `Modifiers' in the section `History Expansion'), are
1391 applied to the words of the value at this level.
1392 8. Character evaluation
1394 Any `(#)' flag is applied, evaluating the result so far numeri‐
1395 cally as a character.
1396 9. Length
1398 Any initial `#' modifier, i.e. in the form ${#var}, is used to
1399 evaluate the length of the expression so far.
1400 10. Forced joining
1402 If the `(j)' flag is present, or no `(j)' flag is present but
1403 the string is to be split as given by rule 11., and joining did
1404 not take place at rule 5., any words in the value are joined to‐
1405 gether using the given string or the first character of $IFS if
1406 none. Note that the `(F)' flag implicitly supplies a string for
1407 joining in this manner.
1408 11. Simple word splitting
1410 If one of the `(s)' or `(f)' flags are present, or the `=' spec‐
1411 ifier was present (e.g. ${=var}), the word is split on occur‐
1412 rences of the specified string, or (for = with neither of the
1413 two flags present) any of the characters in $IFS.
1414 If no `(s)', `(f)' or `=' was given, but the word is not quoted
1416 and the option SH_WORD_SPLIT is set, the word is split on occur‐
1417 rences of any of the characters in $IFS. Note this step, too,
1418 takes place at all levels of a nested substitution.
1419 12. Case modification
1421 Any case modification from one of the flags `(L)', `(U)' or
1422 `(C)' is applied.
1423 13. Escape sequence replacement
1425 First any replacements from the `(g)' flag are performed, then
1426 any prompt-style formatting from the `(%)' family of flags is
1427 applied.
1428 14. Quote application
1430 Any quoting or unquoting using `(q)' and `(Q)' and related flags
1431 is applied.
1432 15. Directory naming
1434 Any directory name substitution using `(D)' flag is applied.
1435 16. Visibility enhancement
1437 Any modifications to make characters visible using the `(V)'
1438 flag are applied.
1439 17. Lexical word splitting
1441 If the '(z)' flag or one of the forms of the '(Z)' flag is
1442 present, the word is split as if it were a shell command line,
1443 so that quotation marks and other metacharacters are used to de‐
1444 cide what constitutes a word. Note this form of splitting is
1445 entirely distinct from that described by rule 11.: it does not
1446 use $IFS, and does not cause forced joining.
1447 18. Uniqueness
1449 If the result is an array and the `(u)' flag was present, dupli‐
1450 cate elements are removed from the array.
1451 19. Ordering
1453 If the result is still an array and one of the `(o)' or `(O)'
1454 flags was present, the array is reordered.
1455 20. RC_EXPAND_PARAM
1457 At this point the decision is made whether any resulting array
1458 elements are to be combined element by element with surrounding
1459 text, as given by either the RC_EXPAND_PARAM option or the `^'
1460 flag.
1461 21. Re-evaluation
1463 Any `(e)' flag is applied to the value, forcing it to be re-ex‐
1464 amined for new parameter substitutions, but also for command and
1465 arithmetic substitutions.
1466 22. Padding
1468 Any padding of the value by the `(l.fill.)' or `(r.fill.)' flags
1469 is applied.
1470 23. Semantic joining
1472 In contexts where expansion semantics requires a single word to
1473 result, all words are rejoined with the first character of IFS
1474 between. So in `${(P)${(f)lines}}' the value of ${lines} is
1475 split at newlines, but then must be joined again before the
1476 `(P)' flag can be applied.
1477 If a single word is not required, this rule is skipped.
1479 24. Empty argument removal
1481 If the substitution does not appear in double quotes, any re‐
1482 sulting zero-length argument, whether from a scalar or an ele‐
1483 ment of an array, is elided from the list of arguments inserted
1484 into the command line.
1485 Strictly speaking, the removal happens later as the same happens
1487 with other forms of substitution; the point to note here is sim‐
1488 ply that it occurs after any of the above parameter operations.
1489 25. Nested parameter name replacement
1491 If the `(P)' flag is present and rule 4. has not applied, the
1492 value so far is treated as a parameter name (which may include a
1493 subscript expression) and replaced with the corresponding value,
1494 with internal flags (rule 2.) applied to the new value.
1495 Examples
1497 The flag f is useful to split a double-quoted substitution line by
1498 line. For example, ${(f)"$(<file)"} substitutes the contents of file
1499 divided so that each line is an element of the resulting array. Com‐
1500 pare this with the effect of $(<file) alone, which divides the file up
1501 by words, or the same inside double quotes, which makes the entire con‐
1502 tent of the file a single string.
1503 The following illustrates the rules for nested parameter expansions.
1505 Suppose that $foo contains the array (bar baz):
1506 "${(@)${foo}[1]}"
1508 This produces the result b. First, the inner substitution
1509 "${foo}", which has no array (@) flag, produces a single word
1510 result "bar baz". The outer substitution "${(@)...[1]}" detects
1511 that this is a scalar, so that (despite the `(@)' flag) the sub‐
1512 script picks the first character.
1513 "${${(@)foo}[1]}"
1515 This produces the result `bar'. In this case, the inner substi‐
1516 tution "${(@)foo}" produces the array `(bar baz)'. The outer
1517 substitution "${...[1]}" detects that this is an array and picks
1518 the first word. This is similar to the simple case "${foo[1]}".
1519 As an example of the rules for word splitting and joining, suppose $foo
1521 contains the array `(ax1 bx1)'. Then
1522 ${(s/x/)foo}
1524 produces the words `a', `1 b' and `1'.
1525 ${(j/x/s/x/)foo}
1527 produces `a', `1', `b' and `1'.
1528 ${(s/x/)foo%%1*}
1530 produces `a' and ` b' (note the extra space). As substitution
1531 occurs before either joining or splitting, the operation first
1532 generates the modified array (ax bx), which is joined to give
1533 "ax bx", and then split to give `a', ` b' and `'. The final
1534 empty string will then be elided, as it is not in double quotes.
1535
1537 A command enclosed in parentheses preceded by a dollar sign, like
1538 `$(...)', or quoted with grave accents, like ``...`', is replaced with
1539 its standard output, with any trailing newlines deleted. If the sub‐
1540 stitution is not enclosed in double quotes, the output is broken into
1541 words using the IFS parameter.
1542 The substitution `$(cat foo)' may be replaced by the faster `$(<foo)'.
1544 In this case foo undergoes single word shell expansions (parameter ex‐
1545 pansion, command substitution and arithmetic expansion), but not file‐
1546 name generation.
1547 If the option GLOB_SUBST is set, the result of any unquoted command
1549 substitution, including the special form just mentioned, is eligible
1550 for filename generation.
1551
1553 A string of the form `$[exp]' or `$((exp))' is substituted with the
1554 value of the arithmetic expression exp. exp is subjected to parameter
1555 expansion, command substitution and arithmetic expansion before it is
1556 evaluated. See the section `Arithmetic Evaluation'.
1557
1559 A string of the form `foo{xx,yy,zz}bar' is expanded to the individual
1560 words `fooxxbar', `fooyybar' and `foozzbar'. Left-to-right order is
1561 preserved. This construct may be nested. Commas may be quoted in or‐
1562 der to include them literally in a word.
1563 An expression of the form `{n1..n2}', where n1 and n2 are integers, is
1565 expanded to every number between n1 and n2 inclusive. If either number
1566 begins with a zero, all the resulting numbers will be padded with lead‐
1567 ing zeroes to that minimum width, but for negative numbers the - char‐
1568 acter is also included in the width. If the numbers are in decreasing
1569 order the resulting sequence will also be in decreasing order.
1570 An expression of the form `{n1..n2..n3}', where n1, n2, and n3 are in‐
1572 tegers, is expanded as above, but only every n3th number starting from
1573 n1 is output. If n3 is negative the numbers are output in reverse or‐
1574 der, this is slightly different from simply swapping n1 and n2 in the
1575 case that the step n3 doesn't evenly divide the range. Zero padding
1576 can be specified in any of the three numbers, specifying it in the
1577 third can be useful to pad for example `{-99..100..01}' which is not
1578 possible to specify by putting a 0 on either of the first two numbers
1579 (i.e. pad to two characters).
1580 An expression of the form `{c1..c2}', where c1 and c2 are single char‐
1582 acters (which may be multibyte characters), is expanded to every char‐
1583 acter in the range from c1 to c2 in whatever character sequence is used
1584 internally. For characters with code points below 128 this is US ASCII
1585 (this is the only case most users will need). If any intervening char‐
1586 acter is not printable, appropriate quotation is used to render it
1587 printable. If the character sequence is reversed, the output is in re‐
1588 verse order, e.g. `{d..a}' is substituted as `d c b a'.
1589 If a brace expression matches none of the above forms, it is left un‐
1591 changed, unless the option BRACE_CCL (an abbreviation for `brace char‐
1592 acter class') is set. In that case, it is expanded to a list of the
1593 individual characters between the braces sorted into the order of the
1594 characters in the ASCII character set (multibyte characters are not
1595 currently handled). The syntax is similar to a [...] expression in
1596 filename generation: `-' is treated specially to denote a range of
1597 characters, but `^' or `!' as the first character is treated normally.
1598 For example, `{abcdef0-9}' expands to 16 words 0 1 2 3 4 5 6 7 8 9 a b
1599 c d e f.
1600 Note that brace expansion is not part of filename generation (glob‐
1602 bing); an expression such as */{foo,bar} is split into two separate
1603 words */foo and */bar before filename generation takes place. In par‐
1604 ticular, note that this is liable to produce a `no match' error if ei‐
1605 ther of the two expressions does not match; this is to be contrasted
1606 with */(foo|bar), which is treated as a single pattern but otherwise
1607 has similar effects.
1608 To combine brace expansion with array expansion, see the ${^spec} form
1610 described in the section Parameter Expansion above.
1611
1613 Each word is checked to see if it begins with an unquoted `~'. If it
1614 does, then the word up to a `/', or the end of the word if there is no
1615 `/', is checked to see if it can be substituted in one of the ways de‐
1616 scribed here. If so, then the `~' and the checked portion are replaced
1617 with the appropriate substitute value.
1618 A `~' by itself is replaced by the value of $HOME. A `~' followed by a
1620 `+' or a `-' is replaced by current or previous working directory, re‐
1621 spectively.
1622 A `~' followed by a number is replaced by the directory at that posi‐
1624 tion in the directory stack. `~0' is equivalent to `~+', and `~1' is
1625 the top of the stack. `~+' followed by a number is replaced by the di‐
1626 rectory at that position in the directory stack. `~+0' is equivalent
1627 to `~+', and `~+1' is the top of the stack. `~-' followed by a number
1628 is replaced by the directory that many positions from the bottom of the
1629 stack. `~-0' is the bottom of the stack. The PUSHD_MINUS option ex‐
1630 changes the effects of `~+' and `~-' where they are followed by a num‐
1631 ber.
1632 Dynamic named directories
1634 If the function zsh_directory_name exists, or the shell variable
1635 zsh_directory_name_functions exists and contains an array of function
1636 names, then the functions are used to implement dynamic directory nam‐
1637 ing. The functions are tried in order until one returns status zero,
1638 so it is important that functions test whether they can handle the case
1639 in question and return an appropriate status.
1640 A `~' followed by a string namstr in unquoted square brackets is
1642 treated specially as a dynamic directory name. Note that the first un‐
1643 quoted closing square bracket always terminates namstr. The shell
1644 function is passed two arguments: the string n (for name) and namstr.
1645 It should either set the array reply to a single element which is the
1646 directory corresponding to the name and return status zero (executing
1647 an assignment as the last statement is usually sufficient), or it
1648 should return status non-zero. In the former case the element of reply
1649 is used as the directory; in the latter case the substitution is deemed
1650 to have failed. If all functions fail and the option NOMATCH is set,
1651 an error results.
1652 The functions defined as above are also used to see if a directory can
1654 be turned into a name, for example when printing the directory stack or
1655 when expanding %~ in prompts. In this case each function is passed two
1656 arguments: the string d (for directory) and the candidate for dynamic
1657 naming. The function should either return non-zero status, if the di‐
1658 rectory cannot be named by the function, or it should set the array re‐
1659 ply to consist of two elements: the first is the dynamic name for the
1660 directory (as would appear within `~[...]'), and the second is the pre‐
1661 fix length of the directory to be replaced. For example, if the trial
1662 directory is /home/myname/src/zsh and the dynamic name for /home/my‐
1663 name/src (which has 16 characters) is s, then the function sets
1664 reply=(s 16)
1666 The directory name so returned is compared with possible static names
1668 for parts of the directory path, as described below; it is used if the
1669 prefix length matched (16 in the example) is longer than that matched
1670 by any static name.
1671 It is not a requirement that a function implements both n and d calls;
1673 for example, it might be appropriate for certain dynamic forms of ex‐
1674 pansion not to be contracted to names. In that case any call with the
1675 first argument d should cause a non-zero status to be returned.
1676 The completion system calls `zsh_directory_name c' followed by equiva‐
1678 lent calls to elements of the array zsh_directory_name_functions, if it
1679 exists, in order to complete dynamic names for directories. The code
1680 for this should be as for any other completion function as described in
1681 zshcompsys(1).
1682 As a working example, here is a function that expands any dynamic names
1684 beginning with the string p: to directories below /home/pws/perforce.
1685 In this simple case a static name for the directory would be just as
1686 effective.
1687 zsh_directory_name() {
1689 emulate -L zsh
1690 setopt extendedglob
1691 local -a match mbegin mend
1692 if [[ $1 = d ]]; then
1693 # turn the directory into a name
1694 if [[ $2 = (#b)(/home/pws/perforce/)([^/]##)* ]]; then
1695 typeset -ga reply
1696 reply=(p:$match[2] $(( ${#match[1]} + ${#match[2]} )) )
1697 else
1698 return 1
1699 fi
1700 elif [[ $1 = n ]]; then
1701 # turn the name into a directory
1702 [[ $2 != (#b)p:(?*) ]] && return 1
1703 typeset -ga reply
1704 reply=(/home/pws/perforce/$match[1])
1705 elif [[ $1 = c ]]; then
1706 # complete names
1707 local expl
1708 local -a dirs
1709 dirs=(/home/pws/perforce/*(/:t))
1710 dirs=(p:${^dirs})
1711 _wanted dynamic-dirs expl 'dynamic directory' compadd -S\] -a dirs
1712 return
1713 else
1714 return 1
1715 fi
1716 return 0
1717 }
1718 Static named directories
1720 A `~' followed by anything not already covered consisting of any number
1721 of alphanumeric characters or underscore (`_'), hyphen (`-'), or dot
1722 (`.') is looked up as a named directory, and replaced by the value of
1723 that named directory if found. Named directories are typically home
1724 directories for users on the system. They may also be defined if the
1725 text after the `~' is the name of a string shell parameter whose value
1726 begins with a `/'. Note that trailing slashes will be removed from the
1727 path to the directory (though the original parameter is not modified).
1728 It is also possible to define directory names using the -d option to
1730 the hash builtin.
1731 When the shell prints a path (e.g. when expanding %~ in prompts or when
1733 printing the directory stack), the path is checked to see if it has a
1734 named directory as its prefix. If so, then the prefix portion is re‐
1735 placed with a `~' followed by the name of the directory. The shorter
1736 of the two ways of referring to the directory is used, i.e. either the
1737 directory name or the full path; the name is used if they are the same
1738 length. The parameters $PWD and $OLDPWD are never abbreviated in this
1739 fashion.
1740 `=' expansion
1742 If a word begins with an unquoted `=' and the EQUALS option is set, the
1743 remainder of the word is taken as the name of a command. If a command
1744 exists by that name, the word is replaced by the full pathname of the
1745 command.
1746 Notes
1748 Filename expansion is performed on the right hand side of a parameter
1749 assignment, including those appearing after commands of the typeset
1750 family. In this case, the right hand side will be treated as a
1751 colon-separated list in the manner of the PATH parameter, so that a `~'
1752 or an `=' following a `:' is eligible for expansion. All such behav‐
1753 iour can be disabled by quoting the `~', the `=', or the whole expres‐
1754 sion (but not simply the colon); the EQUALS option is also respected.
1755 If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in
1757 the form `identifier=expression' becomes eligible for file expansion as
1758 described in the previous paragraph. Quoting the first `=' also in‐
1759 hibits this.
1760
1762 If a word contains an unquoted instance of one of the characters `*',
1763 `(', `|', `<', `[', or `?', it is regarded as a pattern for filename
1764 generation, unless the GLOB option is unset. If the EXTENDED_GLOB op‐
1765 tion is set, the `^' and `#' characters also denote a pattern; other‐
1766 wise they are not treated specially by the shell.
1767 The word is replaced with a list of sorted filenames that match the
1769 pattern. If no matching pattern is found, the shell gives an error
1770 message, unless the NULL_GLOB option is set, in which case the word is
1771 deleted; or unless the NOMATCH option is unset, in which case the word
1772 is left unchanged.
1773 In filename generation, the character `/' must be matched explicitly;
1775 also, a `.' must be matched explicitly at the beginning of a pattern or
1776 after a `/', unless the GLOB_DOTS option is set. No filename genera‐
1777 tion pattern matches the files `.' or `..'. In other instances of pat‐
1778 tern matching, the `/' and `.' are not treated specially.
1779 Glob Operators
1781 * Matches any string, including the null string.
1782 ? Matches any character.
1784 [...] Matches any of the enclosed characters. Ranges of characters
1786 can be specified by separating two characters by a `-'. A `-'
1787 or `]' may be matched by including it as the first character in
1788 the list. There are also several named classes of characters,
1789 in the form `[:name:]' with the following meanings. The first
1790 set use the macros provided by the operating system to test for
1791 the given character combinations, including any modifications
1792 due to local language settings, see ctype(3):
1793 [:alnum:]
1795 The character is alphanumeric
1796 [:alpha:]
1798 The character is alphabetic
1799 [:ascii:]
1801 The character is 7-bit, i.e. is a single-byte character
1802 without the top bit set.
1803 [:blank:]
1805 The character is a blank character
1806 [:cntrl:]
1808 The character is a control character
1809 [:digit:]
1811 The character is a decimal digit
1812 [:graph:]
1814 The character is a printable character other than white‐
1815 space
1816 [:lower:]
1818 The character is a lowercase letter
1819 [:print:]
1821 The character is printable
1822 [:punct:]
1824 The character is printable but neither alphanumeric nor
1825 whitespace
1826 [:space:]
1828 The character is whitespace
1829 [:upper:]
1831 The character is an uppercase letter
1832 [:xdigit:]
1834 The character is a hexadecimal digit
1835 Another set of named classes is handled internally by the shell
1837 and is not sensitive to the locale:
1838 [:IDENT:]
1840 The character is allowed to form part of a shell identi‐
1841 fier, such as a parameter name
1842 [:IFS:]
1844 The character is used as an input field separator, i.e.
1845 is contained in the IFS parameter
1846 [:IFSSPACE:]
1848 The character is an IFS white space character; see the
1849 documentation for IFS in the zshparam(1) manual page.
1850 [:INCOMPLETE:]
1852 Matches a byte that starts an incomplete multibyte char‐
1853 acter. Note that there may be a sequence of more than
1854 one bytes that taken together form the prefix of a multi‐
1855 byte character. To test for a potentially incomplete
1856 byte sequence, use the pattern `[[:INCOMPLETE:]]*'. This
1857 will never match a sequence starting with a valid multi‐
1858 byte character.
1859 [:INVALID:]
1861 Matches a byte that does not start a valid multibyte
1862 character. Note this may be a continuation byte of an
1863 incomplete multibyte character as any part of a multibyte
1864 string consisting of invalid and incomplete multibyte
1865 characters is treated as single bytes.
1866 [:WORD:]
1868 The character is treated as part of a word; this test is
1869 sensitive to the value of the WORDCHARS parameter
1870 Note that the square brackets are additional to those enclosing
1872 the whole set of characters, so to test for a single alphanu‐
1873 meric character you need `[[:alnum:]]'. Named character sets
1874 can be used alongside other types, e.g. `[[:alpha:]0-9]'.
1875 [^...]
1877 [!...] Like [...], except that it matches any character which is not in
1878 the given set.
1879 <[x]-[y]>
1881 Matches any number in the range x to y, inclusive. Either of
1882 the numbers may be omitted to make the range open-ended; hence
1883 `<->' matches any number. To match individual digits, the [...]
1884 form is more efficient.
1885 Be careful when using other wildcards adjacent to patterns of
1887 this form; for example, <0-9>* will actually match any number
1888 whatsoever at the start of the string, since the `<0-9>' will
1889 match the first digit, and the `*' will match any others. This
1890 is a trap for the unwary, but is in fact an inevitable conse‐
1891 quence of the rule that the longest possible match always suc‐
1892 ceeds. Expressions such as `<0-9>[^[:digit:]]*' can be used in‐
1893 stead.
1894 (...) Matches the enclosed pattern. This is used for grouping. If
1896 the KSH_GLOB option is set, then a `@', `*', `+', `?' or `!' im‐
1897 mediately preceding the `(' is treated specially, as detailed
1898 below. The option SH_GLOB prevents bare parentheses from being
1899 used in this way, though the KSH_GLOB option is still available.
1900 Note that grouping cannot extend over multiple directories: it
1902 is an error to have a `/' within a group (this only applies for
1903 patterns used in filename generation). There is one exception:
1904 a group of the form (pat/)# appearing as a complete path segment
1905 can match a sequence of directories. For example, foo/(a*/)#bar
1906 matches foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.
1907 x|y Matches either x or y. This operator has lower precedence than
1909 any other. The `|' character must be within parentheses, to
1910 avoid interpretation as a pipeline. The alternatives are tried
1911 in order from left to right.
1912 ^x (Requires EXTENDED_GLOB to be set.) Matches anything except the
1914 pattern x. This has a higher precedence than `/', so `^foo/bar'
1915 will search directories in `.' except `./foo' for a file named
1916 `bar'.
1917 x~y (Requires EXTENDED_GLOB to be set.) Match anything that matches
1919 the pattern x but does not match y. This has lower precedence
1920 than any operator except `|', so `*/*~foo/bar' will search for
1921 all files in all directories in `.' and then exclude `foo/bar'
1922 if there was such a match. Multiple patterns can be excluded by
1923 `foo~bar~baz'. In the exclusion pattern (y), `/' and `.' are
1924 not treated specially the way they usually are in globbing.
1925 x# (Requires EXTENDED_GLOB to be set.) Matches zero or more occur‐
1927 rences of the pattern x. This operator has high precedence;
1928 `12#' is equivalent to `1(2#)', rather than `[1m(12)#'. It is an
1929 error for an unquoted `#' to follow something which cannot be
1930 repeated; this includes an empty string, a pattern already fol‐
1931 lowed by `##', or parentheses when part of a KSH_GLOB pattern
1932 (for example, `!(foo)#' is invalid and must be replaced by
1933 `*(!(foo))').
1934 x## (Requires EXTENDED_GLOB to be set.) Matches one or more occur‐
1936 rences of the pattern x. This operator has high precedence;
1937 `12##' is equivalent to `1(2##)', rather than `[1m(12)##'. No more
1938 than two active `#' characters may appear together. (Note the
1939 potential clash with glob qualifiers in the form `1(2##)' which
1940 should therefore be avoided.)
1941 ksh-like Glob Operators
1943 If the KSH_GLOB option is set, the effects of parentheses can be modi‐
1944 fied by a preceding `@', `*', `+', `?' or `!'. This character need not
1945 be unquoted to have special effects, but the `(' must be.
1946 @(...) Match the pattern in the parentheses. (Like `(...)'.)
1948 *(...) Match any number of occurrences. (Like `(...)#', except that
1950 recursive directory searching is not supported.)
1951 +(...) Match at least one occurrence. (Like `(...)##', except that re‐
1953 cursive directory searching is not supported.)
1954 ?(...) Match zero or one occurrence. (Like `(|...)'.)
1956 !(...) Match anything but the expression in parentheses. (Like
1958 `(^(...))'.)
1959 Precedence
1961 The precedence of the operators given above is (highest) `^', `/', `~',
1962 `|' (lowest); the remaining operators are simply treated from left to
1963 right as part of a string, with `#' and `##' applying to the shortest
1964 possible preceding unit (i.e. a character, `?', `[...]', `<...>', or a
1965 parenthesised expression). As mentioned above, a `/' used as a direc‐
1966 tory separator may not appear inside parentheses, while a `|' must do
1967 so; in patterns used in other contexts than filename generation (for
1968 example, in case statements and tests within `[[...]]'), a `/' is not
1969 special; and `/' is also not special after a `~' appearing outside
1970 parentheses in a filename pattern.
1971 Globbing Flags
1973 There are various flags which affect any text to their right up to the
1974 end of the enclosing group or to the end of the pattern; they require
1975 the EXTENDED_GLOB option. All take the form (#X) where X may have one
1976 of the following forms:
1977 i Case insensitive: upper or lower case characters in the pattern
1979 match upper or lower case characters.
1980 l Lower case characters in the pattern match upper or lower case
1982 characters; upper case characters in the pattern still only
1983 match upper case characters.
1984 I Case sensitive: locally negates the effect of i or l from that
1986 point on.
1987 b Activate backreferences for parenthesised groups in the pattern;
1989 this does not work in filename generation. When a pattern with
1990 a set of active parentheses is matched, the strings matched by
1991 the groups are stored in the array $match, the indices of the
1992 beginning of the matched parentheses in the array $mbegin, and
1993 the indices of the end in the array $mend, with the first ele‐
1994 ment of each array corresponding to the first parenthesised
1995 group, and so on. These arrays are not otherwise special to the
1996 shell. The indices use the same convention as does parameter
1997 substitution, so that elements of $mend and $mbegin may be used
1998 in subscripts; the KSH_ARRAYS option is respected. Sets of
1999 globbing flags are not considered parenthesised groups; only the
2000 first nine active parentheses can be referenced.
2001 For example,
2003 foo="a_string_with_a_message"
2005 if [[ $foo = (a|an)_(#b)(*) ]]; then
2006 print ${foo[$mbegin[1],$mend[1]]}
2007 fi
2008 prints `string_with_a_message'. Note that the first set of
2010 parentheses is before the (#b) and does not create a backrefer‐
2011 ence.
2012 Backreferences work with all forms of pattern matching other
2014 than filename generation, but note that when performing matches
2015 on an entire array, such as ${array#pattern}, or a global sub‐
2016 stitution, such as ${param//pat/repl}, only the data for the
2017 last match remains available. In the case of global replace‐
2018 ments this may still be useful. See the example for the m flag
2019 below.
2020 The numbering of backreferences strictly follows the order of
2022 the opening parentheses from left to right in the pattern
2023 string, although sets of parentheses may be nested. There are
2024 special rules for parentheses followed by `#' or `##'. Only the
2025 last match of the parenthesis is remembered: for example, in `[[
2026 abab = (#b)([ab])# ]]', only the final `b' is stored in
2027 match[1]. Thus extra parentheses may be necessary to match the
2028 complete segment: for example, use `X((ab|cd)#)Y' to match a
2029 whole string of either `ab' or `cd' between `X' and `Y', using
2030 the value of $match[1] rather than $match[2].
2031 If the match fails none of the parameters is altered, so in some
2033 cases it may be necessary to initialise them beforehand. If
2034 some of the backreferences fail to match -- which happens if
2035 they are in an alternate branch which fails to match, or if they
2036 are followed by # and matched zero times -- then the matched
2037 string is set to the empty string, and the start and end indices
2038 are set to -1.
2039 Pattern matching with backreferences is slightly slower than
2041 without.
2042 B Deactivate backreferences, negating the effect of the b flag
2044 from that point on.
2045 cN,M The flag (#cN,M) can be used anywhere that the # or ## operators
2047 can be used except in the expressions `(*/)#' and `(*/)##' in
2048 filename generation, where `/' has special meaning; it cannot be
2049 combined with other globbing flags and a bad pattern error oc‐
2050 curs if it is misplaced. It is equivalent to the form {N,M} in
2051 regular expressions. The previous character or group is re‐
2052 quired to match between N and M times, inclusive. The form
2053 (#cN) requires exactly N matches; (#c,M) is equivalent to speci‐
2054 fying N as 0; (#cN,) specifies that there is no maximum limit on
2055 the number of matches.
2056 m Set references to the match data for the entire string matched;
2058 this is similar to backreferencing and does not work in filename
2059 generation. The flag must be in effect at the end of the pat‐
2060 tern, i.e. not local to a group. The parameters $MATCH, $MBEGIN
2061 and $MEND will be set to the string matched and to the indices
2062 of the beginning and end of the string, respectively. This is
2063 most useful in parameter substitutions, as otherwise the string
2064 matched is obvious.
2065 For example,
2067 arr=(veldt jynx grimps waqf zho buck)
2069 print ${arr//(#m)[aeiou]/${(U)MATCH}}
2070 forces all the matches (i.e. all vowels) into uppercase, print‐
2072 ing `vEldt jynx grImps wAqf zhO bUck'.
2073 Unlike backreferences, there is no speed penalty for using match
2075 references, other than the extra substitutions required for the
2076 replacement strings in cases such as the example shown.
2077 M Deactivate the m flag, hence no references to match data will be
2079 created.
2080 anum Approximate matching: num errors are allowed in the string
2082 matched by the pattern. The rules for this are described in the
2083 next subsection.
2084 s, e Unlike the other flags, these have only a local effect, and each
2086 must appear on its own: `(#s)' and `(#e)' are the only valid
2087 forms. The `(#s)' flag succeeds only at the start of the test
2088 string, and the `(#e)' flag succeeds only at the end of the test
2089 string; they correspond to `^' and `$' in standard regular ex‐
2090 pressions. They are useful for matching path segments in pat‐
2091 terns other than those in filename generation (where path seg‐
2092 ments are in any case treated separately). For example,
2093 `*((#s)|/)test((#e)|/)*' matches a path segment `test' in any of
2094 the following strings: test, test/at/start, at/end/test,
2095 in/test/middle.
2096 Another use is in parameter substitution; for example `${ar‐
2098 ray/(#s)A*Z(#e)}' will remove only elements of an array which
2099 match the complete pattern `A*Z'. There are other ways of per‐
2100 forming many operations of this type, however the combination of
2101 the substitution operations `/' and `//' with the `(#s)' and
2102 `(#e)' flags provides a single simple and memorable method.
2103 Note that assertions of the form `(^(#s))' also work, i.e. match
2105 anywhere except at the start of the string, although this actu‐
2106 ally means `anything except a zero-length portion at the start
2107 of the string'; you need to use `(""~(#s))' to match a
2108 zero-length portion of the string not at the start.
2109 q A `q' and everything up to the closing parenthesis of the glob‐
2111 bing flags are ignored by the pattern matching code. This is
2112 intended to support the use of glob qualifiers, see below. The
2113 result is that the pattern `(#b)(*).c(#q.)' can be used both for
2114 globbing and for matching against a string. In the former case,
2115 the `(#q.)' will be treated as a glob qualifier and the `(#b)'
2116 will not be useful, while in the latter case the `(#b)' is use‐
2117 ful for backreferences and the `(#q.)' will be ignored. Note
2118 that colon modifiers in the glob qualifiers are also not applied
2119 in ordinary pattern matching.
2120 u Respect the current locale in determining the presence of multi‐
2122 byte characters in a pattern, provided the shell was compiled
2123 with MULTIBYTE_SUPPORT. This overrides the MULTIBYTE option;
2124 the default behaviour is taken from the option. Compare U.
2125 (Mnemonic: typically multibyte characters are from Unicode in
2126 the UTF-8 encoding, although any extension of ASCII supported by
2127 the system library may be used.)
2128 U All characters are considered to be a single byte long. The op‐
2130 posite of u. This overrides the MULTIBYTE option.
2131 For example, the test string fooxx can be matched by the pattern
2133 (#i)FOOXX, but not by (#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X. The
2134 string (#ia2)readme specifies case-insensitive matching of readme with
2135 up to two errors.
2136 When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB
2138 must be set and the left parenthesis should be preceded by @. Note
2139 also that the flags do not affect letters inside [...] groups, in other
2140 words (#i)[a-z] still matches only lowercase letters. Finally, note
2141 that when examining whole paths case-insensitively every directory must
2142 be searched for all files which match, so that a pattern of the form
2143 (#i)/foo/bar/... is potentially slow.
2144 Approximate Matching
2146 When matching approximately, the shell keeps a count of the errors
2147 found, which cannot exceed the number specified in the (#anum) flags.
2148 Four types of error are recognised:
2149 1. Different characters, as in fooxbar and fooybar.
2151 2. Transposition of characters, as in banana and abnana.
2153 3. A character missing in the target string, as with the pattern
2155 road and target string rod.
2156 4. An extra character appearing in the target string, as with stove
2158 and strove.
2159 Thus, the pattern (#a3)abcd matches dcba, with the errors occurring by
2161 using the first rule twice and the second once, grouping the string as
2162 [d][cb][a] and [a][bc][d].
2163 Non-literal parts of the pattern must match exactly, including charac‐
2165 ters in character ranges: hence (#a1)??? matches strings of length
2166 four, by applying rule 4 to an empty part of the pattern, but not
2167 strings of length two, since all the ? must match. Other characters
2168 which must match exactly are initial dots in filenames (unless the
2169 GLOB_DOTS option is set), and all slashes in filenames, so that a/bc is
2170 two errors from ab/c (the slash cannot be transposed with another char‐
2171 acter). Similarly, errors are counted separately for non-contiguous
2172 strings in the pattern, so that (ab|cd)ef is two errors from aebf.
2173 When using exclusion via the ~ operator, approximate matching is
2175 treated entirely separately for the excluded part and must be activated
2176 separately. Thus, (#a1)README~READ_ME matches READ.ME but not READ_ME,
2177 as the trailing READ_ME is matched without approximation. However,
2178 (#a1)README~(#a1)READ_ME does not match any pattern of the form READ?ME
2179 as all such forms are now excluded.
2180 Apart from exclusions, there is only one overall error count; however,
2182 the maximum errors allowed may be altered locally, and this can be de‐
2183 limited by grouping. For example, (#a1)cat((#a0)dog)fox allows one er‐
2184 ror in total, which may not occur in the dog section, and the pattern
2185 (#a1)cat(#a0)dog(#a1)fox is equivalent. Note that the point at which
2186 an error is first found is the crucial one for establishing whether to
2187 use approximation; for example, (#a1)abc(#a0)xyz will not match
2188 abcdxyz, because the error occurs at the `x', where approximation is
2189 turned off.
2190 Entire path segments may be matched approximately, so that
2192 `(#a1)/foo/d/is/available/at/the/bar' allows one error in any path seg‐
2193 ment. This is much less efficient than without the (#a1), however,
2194 since every directory in the path must be scanned for a possible ap‐
2195 proximate match. It is best to place the (#a1) after any path segments
2196 which are known to be correct.
2197 Recursive Globbing
2199 A pathname component of the form `(foo/)#' matches a path consisting of
2200 zero or more directories matching the pattern foo.
2201 As a shorthand, `**/' is equivalent to `(*/)#'; note that this there‐
2203 fore matches files in the current directory as well as subdirectories.
2204 Thus:
2205 ls -ld -- (*/)#bar
2207 or
2209 ls -ld -- **/bar
2211 does a recursive directory search for files named `bar' (potentially
2213 including the file `bar' in the current directory). This form does not
2214 follow symbolic links; the alternative form `***/' does, but is other‐
2215 wise identical. Neither of these can be combined with other forms of
2216 globbing within the same path segment; in that case, the `*' operators
2217 revert to their usual effect.
2218 Even shorter forms are available when the option GLOB_STAR_SHORT is
2220 set. In that case if no / immediately follows a ** or *** they are
2221 treated as if both a / plus a further * are present. Hence:
2222 setopt GLOBSTARSHORT
2224 ls -ld -- **.c
2225 is equivalent to
2227 ls -ld -- **/*.c
2229 Glob Qualifiers
2231 Patterns used for filename generation may end in a list of qualifiers
2232 enclosed in parentheses. The qualifiers specify which filenames that
2233 otherwise match the given pattern will be inserted in the argument
2234 list.
2235 If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses
2237 containing no `|' or `(' characters (or `~' if it is special) is taken
2238 as a set of glob qualifiers. A glob subexpression that would normally
2239 be taken as glob qualifiers, for example `(^x)', can be forced to be
2240 treated as part of the glob pattern by doubling the parentheses, in
2241 this case producing `((^x))'.
2242 If the option EXTENDED_GLOB is set, a different syntax for glob quali‐
2244 fiers is available, namely `(#qx)' where x is any of the same glob
2245 qualifiers used in the other format. The qualifiers must still appear
2246 at the end of the pattern. However, with this syntax multiple glob
2247 qualifiers may be chained together. They are treated as a logical AND
2248 of the individual sets of flags. Also, as the syntax is unambiguous,
2249 the expression will be treated as glob qualifiers just as long any
2250 parentheses contained within it are balanced; appearance of `|', `(' or
2251 `~' does not negate the effect. Note that qualifiers will be recog‐
2252 nised in this form even if a bare glob qualifier exists at the end of
2253 the pattern, for example `*(#q*)(.)' will recognise executable regular
2254 files if both options are set; however, mixed syntax should probably be
2255 avoided for the sake of clarity. Note that within conditions using the
2256 `[[' form the presence of a parenthesised expression (#q...) at the end
2257 of a string indicates that globbing should be performed; the expression
2258 may include glob qualifiers, but it is also valid if it is simply (#q).
2259 This does not apply to the right hand side of pattern match operators
2260 as the syntax already has special significance.
2261 A qualifier may be any one of the following:
2263 / directories
2265 F `full' (i.e. non-empty) directories. Note that the opposite
2267 sense (^F) expands to empty directories and all non-directories.
2268 Use (/^F) for empty directories.
2269 . plain files
2271 @ symbolic links
2273 = sockets
2275 p named pipes (FIFOs)
2277 * executable plain files (0100 or 0010 or 0001)
2279 % device files (character or block special)
2281 %b block special files
2283 %c character special files
2285 r owner-readable files (0400)
2287 w owner-writable files (0200)
2289 x owner-executable files (0100)
2291 A group-readable files (0040)
2293 I group-writable files (0020)
2295 E group-executable files (0010)
2297 R world-readable files (0004)
2299 W world-writable files (0002)
2301 X world-executable files (0001)
2303 s setuid files (04000)
2305 S setgid files (02000)
2307 t files with the sticky bit (01000)
2309 fspec files with access rights matching spec. This spec may be a octal
2311 number optionally preceded by a `=', a `+', or a `-'. If none of
2312 these characters is given, the behavior is the same as for `='.
2313 The octal number describes the mode bits to be expected, if com‐
2314 bined with a `=', the value given must match the file-modes ex‐
2315 actly, with a `+', at least the bits in the given number must be
2316 set in the file-modes, and with a `-', the bits in the number
2317 must not be set. Giving a `?' instead of a octal digit anywhere
2318 in the number ensures that the corresponding bits in the
2319 file-modes are not checked, this is only useful in combination
2320 with `='.
2321 If the qualifier `f' is followed by any other character anything
2323 up to the next matching character (`[', `{', and `<' match `]',
2324 `}', and `>' respectively, any other character matches itself)
2325 is taken as a list of comma-separated sub-specs. Each sub-spec
2326 may be either an octal number as described above or a list of
2327 any of the characters `u', `g', `o', and `a', followed by a `=',
2328 a `+', or a `-', followed by a list of any of the characters
2329 `r', `w', `x', `s', and `t', or an octal digit. The first list
2330 of characters specify which access rights are to be checked. If
2331 a `u' is given, those for the owner of the file are used, if a
2332 `g' is given, those of the group are checked, a `o' means to
2333 test those of other users, and the `a' says to test all three
2334 groups. The `=', `+', and `-' again says how the modes are to be
2335 checked and have the same meaning as described for the first
2336 form above. The second list of characters finally says which ac‐
2337 cess rights are to be expected: `r' for read access, `w' for
2338 write access, `x' for the right to execute the file (or to
2339 search a directory), `s' for the setuid and setgid bits, and `t'
2340 for the sticky bit.
2341 Thus, `*(f70?)' gives the files for which the owner has read,
2343 write, and execute permission, and for which other group members
2344 have no rights, independent of the permissions for other users.
2345 The pattern `*(f-100)' gives all files for which the owner does
2346 not have execute permission, and `*(f:gu+w,o-rx:)' gives the
2347 files for which the owner and the other members of the group
2348 have at least write permission, and for which other users don't
2349 have read or execute permission.
2350 estring
2352 +cmd The string will be executed as shell code. The filename will be
2353 included in the list if and only if the code returns a zero sta‐
2354 tus (usually the status of the last command).
2355 In the first form, the first character after the `e' will be
2357 used as a separator and anything up to the next matching separa‐
2358 tor will be taken as the string; `[', `{', and `<' match `]',
2359 `}', and `>', respectively, while any other character matches
2360 itself. Note that expansions must be quoted in the string to
2361 prevent them from being expanded before globbing is done.
2362 string is then executed as shell code. The string globqual is
2363 appended to the array zsh_eval_context the duration of execu‐
2364 tion.
2365 During the execution of string the filename currently being
2367 tested is available in the parameter REPLY; the parameter may be
2368 altered to a string to be inserted into the list instead of the
2369 original filename. In addition, the parameter reply may be set
2370 to an array or a string, which overrides the value of REPLY. If
2371 set to an array, the latter is inserted into the command line
2372 word by word.
2373 For example, suppose a directory contains a single file
2375 `lonely'. Then the expression `*(e:'reply=(${REPLY}{1,2})':)'
2376 will cause the words `lonely1' and `lonely2' to be inserted into
2377 the command line. Note the quoting of string.
2378 The form +cmd has the same effect, but no delimiters appear
2380 around cmd. Instead, cmd is taken as the longest sequence of
2381 characters following the + that are alphanumeric or underscore.
2382 Typically cmd will be the name of a shell function that contains
2383 the appropriate test. For example,
2384 nt() { [[ $REPLY -nt $NTREF ]] }
2386 NTREF=reffile
2387 ls -ld -- *(+nt)
2388 lists all files in the directory that have been modified more
2390 recently than reffile.
2391 ddev files on the device dev
2393 l[-|+]ct
2395 files having a link count less than ct (-), greater than ct (+),
2396 or equal to ct
2397 U files owned by the effective user ID
2399 G files owned by the effective group ID
2401 uid files owned by user ID id if that is a number. Otherwise, id
2403 specifies a user name: the character after the `u' will be taken
2404 as a separator and the string between it and the next matching
2405 separator will be taken as a user name. The starting separators
2406 `[', `{', and `<' match the final separators `]', `}', and `>',
2407 respectively; any other character matches itself. The selected
2408 files are those owned by this user. For example, `u:foo:' or
2409 `u[foo]' selects files owned by user `foo'.
2410 gid like uid but with group IDs or names
2412 a[Mwhms][-|+]n
2414 files accessed exactly n days ago. Files accessed within the
2415 last n days are selected using a negative value for n (-n).
2416 Files accessed more than n days ago are selected by a positive n
2417 value (+n). Optional unit specifiers `M', `w', `h', `m' or `s'
2418 (e.g. `ah5') cause the check to be performed with months (of 30
2419 days), weeks, hours, minutes or seconds instead of days, respec‐
2420 tively. An explicit `d' for days is also allowed.
2421 Any fractional part of the difference between the access time
2423 and the current part in the appropriate units is ignored in the
2424 comparison. For instance, `echo *(ah-5)' would echo files ac‐
2425 cessed within the last five hours, while `echo *(ah+5)' would
2426 echo files accessed at least six hours ago, as times strictly
2427 between five and six hours are treated as five hours.
2428 m[Mwhms][-|+]n
2430 like the file access qualifier, except that it uses the file
2431 modification time.
2432 c[Mwhms][-|+]n
2434 like the file access qualifier, except that it uses the file in‐
2435 ode change time.
2436 L[+|-]n
2438 files less than n bytes (-), more than n bytes (+), or exactly n
2439 bytes in length.
2440 If this flag is directly followed by a size specifier `k' (`K'),
2442 `m' (`M'), or `p' (`P') (e.g. `Lk-50') the check is performed
2443 with kilobytes, megabytes, or blocks (of 512 bytes) instead.
2444 (On some systems additional specifiers are available for giga‐
2445 bytes, `g' or `G', and terabytes, `t' or `T'.) If a size speci‐
2446 fier is used a file is regarded as "exactly" the size if the
2447 file size rounded up to the next unit is equal to the test size.
2448 Hence `*(Lm1)' matches files from 1 byte up to 1 Megabyte inclu‐
2449 sive. Note also that the set of files "less than" the test size
2450 only includes files that would not match the equality test;
2451 hence `*(Lm-1)' only matches files of zero size.
2452 ^ negates all qualifiers following it
2454 - toggles between making the qualifiers work on symbolic links
2456 (the default) and the files they point to
2457 M sets the MARK_DIRS option for the current pattern
2459 T appends a trailing qualifier mark to the filenames, analogous to
2461 the LIST_TYPES option, for the current pattern (overrides M)
2462 N sets the NULL_GLOB option for the current pattern
2464 D sets the GLOB_DOTS option for the current pattern
2466 n sets the NUMERIC_GLOB_SORT option for the current pattern
2468 Yn enables short-circuit mode: the pattern will expand to at most n
2470 filenames. If more than n matches exist, only the first n
2471 matches in directory traversal order will be considered.
2472 Implies oN when no oc qualifier is used.
2474 oc specifies how the names of the files should be sorted. If c is n
2476 they are sorted by name; if it is L they are sorted depending on
2477 the size (length) of the files; if l they are sorted by the num‐
2478 ber of links; if a, m, or c they are sorted by the time of the
2479 last access, modification, or inode change respectively; if d,
2480 files in subdirectories appear before those in the current di‐
2481 rectory at each level of the search -- this is best combined
2482 with other criteria, for example `odon' to sort on names for
2483 files within the same directory; if N, no sorting is performed.
2484 Note that a, m, and c compare the age against the current time,
2485 hence the first name in the list is the youngest file. Also note
2486 that the modifiers ^ and - are used, so `*(^-oL)' gives a list
2487 of all files sorted by file size in descending order, following
2488 any symbolic links. Unless oN is used, multiple order speci‐
2489 fiers may occur to resolve ties.
2490 The default sorting is n (by name) unless the Y glob qualifier
2492 is used, in which case it is N (unsorted).
2493 oe and o+ are special cases; they are each followed by shell
2495 code, delimited as for the e glob qualifier and the + glob qual‐
2496 ifier respectively (see above). The code is executed for each
2497 matched file with the parameter REPLY set to the name of the
2498 file on entry and globsort appended to zsh_eval_context. The
2499 code should modify the parameter REPLY in some fashion. On re‐
2500 turn, the value of the parameter is used instead of the file
2501 name as the string on which to sort. Unlike other sort opera‐
2502 tors, oe and o+ may be repeated, but note that the maximum num‐
2503 ber of sort operators of any kind that may appear in any glob
2504 expression is 12.
2505 Oc like `o', but sorts in descending order; i.e. `*(^oc)' is the
2507 same as `*(Oc)' and `*(^Oc)' is the same as `*(oc)'; `Od' puts
2508 files in the current directory before those in subdirectories at
2509 each level of the search.
2510 [beg[,end]]
2512 specifies which of the matched filenames should be included in
2513 the returned list. The syntax is the same as for array sub‐
2514 scripts. beg and the optional end may be mathematical expres‐
2515 sions. As in parameter subscripting they may be negative to make
2516 them count from the last match backward. E.g.: `*(-OL[1,3])'
2517 gives a list of the names of the three largest files.
2518 Pstring
2520 The string will be prepended to each glob match as a separate
2521 word. string is delimited in the same way as arguments to the e
2522 glob qualifier described above. The qualifier can be repeated;
2523 the words are prepended separately so that the resulting command
2524 line contains the words in the same order they were given in the
2525 list of glob qualifiers.
2526 A typical use for this is to prepend an option before all occur‐
2528 rences of a file name; for example, the pattern `*(P:-f:)' pro‐
2529 duces the command line arguments `-f file1 -f file2 ...'
2530 If the modifier ^ is active, then string will be appended in‐
2532 stead of prepended. Prepending and appending is done indepen‐
2533 dently so both can be used on the same glob expression; for ex‐
2534 ample by writing `*(P:foo:^P:bar:^P:baz:)' which produces the
2535 command line arguments `foo baz file1 bar ...'
2536 More than one of these lists can be combined, separated by commas. The
2538 whole list matches if at least one of the sublists matches (they are
2539 `or'ed, the qualifiers in the sublists are `and'ed). Some qualifiers,
2540 however, affect all matches generated, independent of the sublist in
2541 which they are given. These are the qualifiers `M', `T', `N', `D',
2542 `n', `o', `O' and the subscripts given in brackets (`[...]').
2543 If a `:' appears in a qualifier list, the remainder of the expression
2545 in parenthesis is interpreted as a modifier (see the section `Modi‐
2546 fiers' in the section `History Expansion'). Each modifier must be in‐
2547 troduced by a separate `:'. Note also that the result after modifica‐
2548 tion does not have to be an existing file. The name of any existing
2549 file can be followed by a modifier of the form `(:...)' even if no ac‐
2550 tual filename generation is performed, although note that the presence
2551 of the parentheses causes the entire expression to be subjected to any
2552 global pattern matching options such as NULL_GLOB. Thus:
2553 ls -ld -- *(-/)
2555 lists all directories and symbolic links that point to directories, and
2557 ls -ld -- *(-@)
2559 lists all broken symbolic links, and
2561 ls -ld -- *(%W)
2563 lists all world-writable device files in the current directory, and
2565 ls -ld -- *(W,X)
2567 lists all files in the current directory that are world-writable or
2569 world-executable, and
2570 print -rC1 /tmp/foo*(u0^@:t)
2572 outputs the basename of all root-owned files beginning with the string
2574 `foo' in /tmp, ignoring symlinks, and
2575 ls -ld -- *.*~(lex|parse).[ch](^D^l1)
2577 lists all files having a link count of one whose names contain a dot
2579 (but not those starting with a dot, since GLOB_DOTS is explicitly
2580 switched off) except for lex.c, lex.h, parse.c and parse.h.
2581 print -rC1 b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)
2583 demonstrates how colon modifiers and other qualifiers may be chained
2585 together. The ordinary qualifier `.' is applied first, then the colon
2586 modifiers in order from left to right. So if EXTENDED_GLOB is set and
2587 the base pattern matches the regular file builtin.pro, the shell will
2588 print `shmiltin.shmo'.
2589zsh 5.8.1 February 12, 2022 ZSHEXPN(1)