1ZSHPARAM(1) General Commands Manual ZSHPARAM(1)
2
6 zshparam - zsh parameters
7
9 A parameter has a name, a value, and a number of attributes. A name
10 may be any sequence of alphanumeric characters and underscores, or the
11 single characters `*', `@', `#', `?', `-', `$', or `!'. A parameter
12 whose name begins with an alphanumeric or underscore is also referred
13 to as a variable.
14 The attributes of a parameter determine the type of its value, often
16 referred to as the parameter type or variable type, and also control
17 other processing that may be applied to the value when it is refer‐
18 enced. The value type may be a scalar (a string, an integer, or a
19 floating point number), an array (indexed numerically), or an associa‐
20 tive array (an unordered set of name-value pairs, indexed by name, also
21 referred to as a hash).
22 Named scalar parameters may have the exported, -x, attribute, to copy
24 them into the process environment, which is then passed from the shell
25 to any new processes that it starts. Exported parameters are called
26 environment variables. The shell also imports environment variables at
27 startup time and automatically marks the corresponding parameters as
28 exported. Some environment variables are not imported for reasons of
29 security or because they would interfere with the correct operation of
30 other shell features.
31 Parameters may also be special, that is, they have a predetermined
33 meaning to the shell. Special parameters cannot have their type
34 changed or their readonly attribute turned off, and if a special param‐
35 eter is unset, then later recreated, the special properties will be re‐
36 tained.
37 To declare the type of a parameter, or to assign a string or numeric
39 value to a scalar parameter, use the typeset builtin.
40 The value of a scalar parameter may also be assigned by writing:
42 name=value
44 In scalar assignment, value is expanded as a single string, in which
46 the elements of arrays are joined together; filename expansion is not
47 performed unless the option GLOB_ASSIGN is set.
48 When the integer attribute, -i, or a floating point attribute, -E or
50 -F, is set for name, the value is subject to arithmetic evaluation.
51 Furthermore, by replacing `=' with `+=', a parameter can be incremented
52 or appended to. See the section `Array Parameters' and Arithmetic
53 Evaluation (in zshmisc(1)) for additional forms of assignment.
54 Note that assignment may implicitly change the attributes of a parame‐
56 ter. For example, assigning a number to a variable in arithmetic eval‐
57 uation may change its type to integer or float, and with GLOB_ASSIGN
58 assigning a pattern to a variable may change its type to an array.
59 To reference the value of a parameter, write `$name' or `${name}'. See
61 Parameter Expansion in zshexpn(1) for complete details. That section
62 also explains the effect of the difference between scalar and array as‐
63 signment on parameter expansion.
64
66 To assign an array value, write one of:
67 set -A name value ...
69 name=(value ...)
70 name=([key]=value ...)
71 If no parameter name exists, an ordinary array parameter is created.
73 If the parameter name exists and is a scalar, it is replaced by a new
74 array.
75 In the third form, key is an expression that will be evaluated in
77 arithmetic context (in its simplest form, an integer) that gives the
78 index of the element to be assigned with value. In this form any ele‐
79 ments not explicitly mentioned that come before the largest index to
80 which a value is assigned are assigned an empty string. The indices
81 may be in any order. Note that this syntax is strict: [ and ]= must
82 not be quoted, and key may not consist of the unquoted string ]=, but
83 is otherwise treated as a simple string. The enhanced forms of sub‐
84 script expression that may be used when directly subscripting a vari‐
85 able name, described in the section `Array Subscripts' below, are not
86 available.
87 The syntaxes with and without the explicit key may be mixed. An im‐
89 plicit key is deduced by incrementing the index from the previously as‐
90 signed element. Note that it is not treated as an error if latter as‐
91 signments in this form overwrite earlier assignments.
92 For example, assuming the option KSH_ARRAYS is not set, the following:
94 array=(one [3]=three four)
96 causes the array variable array to contain four elements one, an empty
98 string, three and four, in that order.
99 In the forms where only value is specified, full command line expansion
101 is performed.
102 In the [key]=value form, both key and value undergo all forms of expan‐
104 sion allowed for single word shell expansions (this does not include
105 filename generation); these are as performed by the parameter expansion
106 flag (e) as described in zshexpn(1). Nested parentheses may surround
107 value and are included as part of the value, which is joined into a
108 plain string; this differs from ksh which allows the values themselves
109 to be arrays. A future version of zsh may support that. To cause the
110 brackets to be interpreted as a character class for filename genera‐
111 tion, and therefore to treat the resulting list of files as a set of
112 values, quote the equal sign using any form of quoting. Example:
113 name=([a-z]'='*)
115 To append to an array without changing the existing values, use one of
117 the following:
118 name+=(value ...)
120 name+=([key]=value ...)
121 In the second form key may specify an existing index as well as an in‐
123 dex off the end of the old array; any existing value is overwritten by
124 value. Also, it is possible to use [key]+=value to append to the ex‐
125 isting value at that index.
126 Within the parentheses on the right hand side of either form of the as‐
128 signment, newlines and semicolons are treated the same as white space,
129 separating individual values. Any consecutive sequence of such charac‐
130 ters has the same effect.
131 Ordinary array parameters may also be explicitly declared with:
133 typeset -a name
135 Associative arrays must be declared before assignment, by using:
137 typeset -A name
139 When name refers to an associative array, the list in an assignment is
141 interpreted as alternating keys and values:
142 set -A name key value ...
144 name=(key value ...)
145 name=([key]=value ...)
146 Note that only one of the two syntaxes above may be used in any given
148 assignment; the forms may not be mixed. This is unlike the case of nu‐
149 merically indexed arrays.
150 Every key must have a value in this case. Note that this assigns to
152 the entire array, deleting any elements that do not appear in the list.
153 The append syntax may also be used with an associative array:
154 name+=(key value ...)
156 name+=([key]=value ...)
157 This adds a new key/value pair if the key is not already present, and
159 replaces the value for the existing key if it is. In the second form
160 it is also possible to use [key]+=value to append to the existing value
161 at that key. Expansion is performed identically to the corresponding
162 forms for normal arrays, as described above.
163 To create an empty array (including associative arrays), use one of:
165 set -A name
167 name=()
168 Array Subscripts
170 Individual elements of an array may be selected using a subscript. A
171 subscript of the form `[exp]' selects the single element exp, where exp
172 is an arithmetic expression which will be subject to arithmetic expan‐
173 sion as if it were surrounded by `$((...))'. The elements are numbered
174 beginning with 1, unless the KSH_ARRAYS option is set in which case
175 they are numbered from zero.
176 Subscripts may be used inside braces used to delimit a parameter name,
178 thus `${foo[2]}' is equivalent to `$foo[2]'. If the KSH_ARRAYS option
179 is set, the braced form is the only one that works, as bracketed ex‐
180 pressions otherwise are not treated as subscripts.
181 If the KSH_ARRAYS option is not set, then by default accesses to an ar‐
183 ray element with a subscript that evaluates to zero return an empty
184 string, while an attempt to write such an element is treated as an er‐
185 ror. For backward compatibility the KSH_ZERO_SUBSCRIPT option can be
186 set to cause subscript values 0 and 1 to be equivalent; see the de‐
187 scription of the option in zshoptions(1).
188 The same subscripting syntax is used for associative arrays, except
190 that no arithmetic expansion is applied to exp. However, the parsing
191 rules for arithmetic expressions still apply, which affects the way
192 that certain special characters must be protected from interpretation.
193 See Subscript Parsing below for details.
194 A subscript of the form `[*]' or `[@]' evaluates to all elements of an
196 array; there is no difference between the two except when they appear
197 within double quotes. `"$foo[*]"' evaluates to `"$foo[1] $foo[2]
198 ..."', whereas `"$foo[@]"' evaluates to `"$foo[1]" "$foo[2]" ...'. For
199 associative arrays, `[*]' or `[@]' evaluate to all the values, in no
200 particular order. Note that this does not substitute the keys; see the
201 documentation for the `k' flag under Parameter Expansion Flags in zsh‐
202 expn(1) for complete details. When an array parameter is referenced as
203 `$name' (with no subscript) it evaluates to `$name[*]', unless the
204 KSH_ARRAYS option is set in which case it evaluates to `${name[0]}'
205 (for an associative array, this means the value of the key `0', which
206 may not exist even if there are values for other keys).
207 A subscript of the form `[exp1,exp2]' selects all elements in the range
209 exp1 to exp2, inclusive. (Associative arrays are unordered, and so do
210 not support ranges.) If one of the subscripts evaluates to a negative
211 number, say -n, then the nth element from the end of the array is used.
212 Thus `$foo[-3]' is the third element from the end of the array foo, and
213 `$foo[1,-1]' is the same as `$foo[*]'.
214 Subscripting may also be performed on non-array values, in which case
216 the subscripts specify a substring to be extracted. For example, if
217 FOO is set to `foobar', then `echo $FOO[2,5]' prints `ooba'. Note that
218 some forms of subscripting described below perform pattern matching,
219 and in that case the substring extends from the start of the match of
220 the first subscript to the end of the match of the second subscript.
221 For example,
222 string="abcdefghijklm"
224 print ${string[(r)d?,(r)h?]}
225 prints `defghi'. This is an obvious generalisation of the rule for
227 single-character matches. For a single subscript, only a single char‐
228 acter is referenced (not the range of characters covered by the match).
229 Note that in substring operations the second subscript is handled dif‐
231 ferently by the r and R subscript flags: the former takes the shortest
232 match as the length and the latter the longest match. Hence in the
233 former case a * at the end is redundant while in the latter case it
234 matches the whole remainder of the string. This does not affect the
235 result of the single subscript case as here the length of the match is
236 irrelevant.
237 Array Element Assignment
239 A subscript may be used on the left side of an assignment like so:
240 name[exp]=value
242 In this form of assignment the element or range specified by exp is re‐
244 placed by the expression on the right side. An array (but not an asso‐
245 ciative array) may be created by assignment to a range or element. Ar‐
246 rays do not nest, so assigning a parenthesized list of values to an el‐
247 ement or range changes the number of elements in the array, shifting
248 the other elements to accommodate the new values. (This is not sup‐
249 ported for associative arrays.)
250 This syntax also works as an argument to the typeset command:
252 typeset "name[exp]"=value
254 The value may not be a parenthesized list in this case; only single-el‐
256 ement assignments may be made with typeset. Note that quotes are nec‐
257 essary in this case to prevent the brackets from being interpreted as
258 filename generation operators. The noglob precommand modifier could be
259 used instead.
260 To delete an element of an ordinary array, assign `()' to that element.
262 To delete an element of an associative array, use the unset command:
263 unset "name[exp]"
265 Subscript Flags
267 If the opening bracket, or the comma in a range, in any subscript ex‐
268 pression is directly followed by an opening parenthesis, the string up
269 to the matching closing one is considered to be a list of flags, as in
270 `name[(flags)exp]'.
271 The flags s, n and b take an argument; the delimiter is shown below as
273 `:', but any character, or the matching pairs `(...)', `{...}',
274 `[...]', or `<...>', may be used, but note that `<...>' can only be
275 used if the subscript is inside a double quoted expression or a parame‐
276 ter substitution enclosed in braces as otherwise the expression is in‐
277 terpreted as a redirection.
278 The flags currently understood are:
280 w If the parameter subscripted is a scalar then this flag makes
282 subscripting work on words instead of characters. The default
283 word separator is whitespace. When combined with the i or I
284 flag, the effect is to produce the index of the first character
285 of the first/last word which matches the given pattern; note
286 that a failed match in this case always yields 0.
287 s:string:
289 This gives the string that separates words (for use with the w
290 flag). The delimiter character : is arbitrary; see above.
291 p Recognize the same escape sequences as the print builtin in the
293 string argument of a subsequent `s' flag.
294 f If the parameter subscripted is a scalar then this flag makes
296 subscripting work on lines instead of characters, i.e. with ele‐
297 ments separated by newlines. This is a shorthand for `pws:\n:'.
298 r Reverse subscripting: if this flag is given, the exp is taken as
300 a pattern and the result is the first matching array element,
301 substring or word (if the parameter is an array, if it is a
302 scalar, or if it is a scalar and the `w' flag is given, respec‐
303 tively). The subscript used is the number of the matching ele‐
304 ment, so that pairs of subscripts such as `$foo[(r)??,3]' and
305 `$foo[(r)??,(r)f*]' are possible if the parameter is not an as‐
306 sociative array. If the parameter is an associative array, only
307 the value part of each pair is compared to the pattern, and the
308 result is that value.
309 If a search through an ordinary array failed, the search sets
311 the subscript to one past the end of the array, and hence ${ar‐
312 ray[(r)pattern]} will substitute the empty string. Thus the
313 success of a search can be tested by using the (i) flag, for ex‐
314 ample (assuming the option KSH_ARRAYS is not in effect):
315 [[ ${array[(i)pattern]} -le ${#array} ]]
317 If KSH_ARRAYS is in effect, the -le should be replaced by -lt.
319 R Like `r', but gives the last match. For associative arrays,
321 gives all possible matches. May be used for assigning to ordi‐
322 nary array elements, but not for assigning to associative ar‐
323 rays. On failure, for normal arrays this has the effect of re‐
324 turning the element corresponding to subscript 0; this is empty
325 unless one of the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in
326 effect.
327 Note that in subscripts with both `r' and `R' pattern characters
329 are active even if they were substituted for a parameter (re‐
330 gardless of the setting of GLOB_SUBST which controls this fea‐
331 ture in normal pattern matching). The flag `e' can be added to
332 inhibit pattern matching. As this flag does not inhibit other
333 forms of substitution, care is still required; using a parameter
334 to hold the key has the desired effect:
335 key2='original key'
337 print ${array[(Re)$key2]}
338 i Like `r', but gives the index of the match instead; this may not
340 be combined with a second argument. On the left side of an as‐
341 signment, behaves like `r'. For associative arrays, the key
342 part of each pair is compared to the pattern, and the first
343 matching key found is the result. On failure substitutes the
344 length of the array plus one, as discussed under the description
345 of `r', or the empty string for an associative array.
346 Note: Although `i' may be applied to a scalar substitution to
348 find the offset of a substring, the results are likely to be
349 misleading when searching within substitutions that yield an
350 empty string, or when searching for the empty substring.
351 I Like `i', but gives the index of the last match, or all possible
353 matching keys in an associative array. On failure substitutes
354 0, or the empty string for an associative array. This flag is
355 best when testing for values or keys that do not exist.
356 Note: If the option KSH_ARRAYS is in effect and no match is
358 found, the result is indistinguishable from the case when the
359 first element of the array matches.
360 k If used in a subscript on an associative array, this flag causes
362 the keys to be interpreted as patterns, and returns the value
363 for the first key found where exp is matched by the key. Note
364 this could be any such key as no ordering of associative arrays
365 is defined. This flag does not work on the left side of an as‐
366 signment to an associative array element. If used on another
367 type of parameter, this behaves like `r'.
368 K On an associative array this is like `k' but returns all values
370 where exp is matched by the keys. On other types of parameters
371 this has the same effect as `R'.
372 n:expr:
374 If combined with `r', `R', `i' or `I', makes them give the nth
375 or nth last match (if expr evaluates to n). This flag is ig‐
376 nored when the array is associative. The delimiter character :
377 is arbitrary; see above.
378 b:expr:
380 If combined with `r', `R', `i' or `I', makes them begin at the
381 nth or nth last element, word, or character (if expr evaluates
382 to n). This flag is ignored when the array is associative. The
383 delimiter character : is arbitrary; see above.
384 e This flag causes any pattern matching that would be performed on
386 the subscript to use plain string matching instead. Hence
387 `${array[(re)*]}' matches only the array element whose value is
388 *. Note that other forms of substitution such as parameter sub‐
389 stitution are not inhibited.
390 This flag can also be used to force * or @ to be interpreted as
392 a single key rather than as a reference to all values. It may
393 be used for either purpose on the left side of an assignment.
394 See Parameter Expansion Flags (zshexpn(1)) for additional ways to ma‐
396 nipulate the results of array subscripting.
397 Subscript Parsing
399 This discussion applies mainly to associative array key strings and to
400 patterns used for reverse subscripting (the `r', `R', `i', etc. flags),
401 but it may also affect parameter substitutions that appear as part of
402 an arithmetic expression in an ordinary subscript.
403 To avoid subscript parsing limitations in assignments to associative
405 array elements, use the append syntax:
406 aa+=('key with "*strange*" characters' 'value string')
408 The basic rule to remember when writing a subscript expression is that
410 all text between the opening `[' and the closing `]' is interpreted as
411 if it were in double quotes (see zshmisc(1)). However, unlike double
412 quotes which normally cannot nest, subscript expressions may appear in‐
413 side double-quoted strings or inside other subscript expressions (or
414 both!), so the rules have two important differences.
415 The first difference is that brackets (`[' and `]') must appear as bal‐
417 anced pairs in a subscript expression unless they are preceded by a
418 backslash (`\'). Therefore, within a subscript expression (and unlike
419 true double-quoting) the sequence `\[' becomes `[', and similarly `\]'
420 becomes `]'. This applies even in cases where a backslash is not nor‐
421 mally required; for example, the pattern `[^[]' (to match any character
422 other than an open bracket) should be written `[^\[]' in a reverse-sub‐
423 script pattern. However, note that `\[^\[\]' and even `\[^[]' mean the
424 same thing, because backslashes are always stripped when they appear
425 before brackets!
426 The same rule applies to parentheses (`(' and `)') and braces (`{' and
428 `}'): they must appear either in balanced pairs or preceded by a back‐
429 slash, and backslashes that protect parentheses or braces are removed
430 during parsing. This is because parameter expansions may be surrounded
431 by balanced braces, and subscript flags are introduced by balanced
432 parentheses.
433 The second difference is that a double-quote (`"') may appear as part
435 of a subscript expression without being preceded by a backslash, and
436 therefore that the two characters `\"' remain as two characters in the
437 subscript (in true double-quoting, `\"' becomes `"'). However, because
438 of the standard shell quoting rules, any double-quotes that appear must
439 occur in balanced pairs unless preceded by a backslash. This makes it
440 more difficult to write a subscript expression that contains an odd
441 number of double-quote characters, but the reason for this difference
442 is so that when a subscript expression appears inside true dou‐
443 ble-quotes, one can still write `\"' (rather than `\\\"') for `"'.
444 To use an odd number of double quotes as a key in an assignment, use
446 the typeset builtin and an enclosing pair of double quotes; to refer to
447 the value of that key, again use double quotes:
448 typeset -A aa
450 typeset "aa[one\"two\"three\"quotes]"=QQQ
451 print "$aa[one\"two\"three\"quotes]"
452 It is important to note that the quoting rules do not change when a pa‐
454 rameter expansion with a subscript is nested inside another subscript
455 expression. That is, it is not necessary to use additional backslashes
456 within the inner subscript expression; they are removed only once, from
457 the innermost subscript outwards. Parameters are also expanded from
458 the innermost subscript first, as each expansion is encountered left to
459 right in the outer expression.
460 A further complication arises from a way in which subscript parsing is
462 not different from double quote parsing. As in true double-quoting,
463 the sequences `\*', and `\@' remain as two characters when they appear
464 in a subscript expression. To use a literal `*' or `@' as an associa‐
465 tive array key, the `e' flag must be used:
466 typeset -A aa
468 aa[(e)*]=star
469 print $aa[(e)*]
470 A last detail must be considered when reverse subscripting is per‐
472 formed. Parameters appearing in the subscript expression are first ex‐
473 panded and then the complete expression is interpreted as a pattern.
474 This has two effects: first, parameters behave as if GLOB_SUBST were on
475 (and it cannot be turned off); second, backslashes are interpreted
476 twice, once when parsing the array subscript and again when parsing the
477 pattern. In a reverse subscript, it's necessary to use four back‐
478 slashes to cause a single backslash to match literally in the pattern.
479 For complex patterns, it is often easiest to assign the desired pattern
480 to a parameter and then refer to that parameter in the subscript, be‐
481 cause then the backslashes, brackets, parentheses, etc., are seen only
482 when the complete expression is converted to a pattern. To match the
483 value of a parameter literally in a reverse subscript, rather than as a
484 pattern, use `${(q)name}' (see zshexpn(1)) to quote the expanded value.
485 Note that the `k' and `K' flags are reverse subscripting for an ordi‐
487 nary array, but are not reverse subscripting for an associative array!
488 (For an associative array, the keys in the array itself are interpreted
489 as patterns by those flags; the subscript is a plain string in that
490 case.)
491 One final note, not directly related to subscripting: the numeric names
493 of positional parameters (described below) are parsed specially, so for
494 example `$2foo' is equivalent to `${2}foo'. Therefore, to use sub‐
495 script syntax to extract a substring from a positional parameter, the
496 expansion must be surrounded by braces; for example, `${2[3,5]}' evalu‐
497 ates to the third through fifth characters of the second positional pa‐
498 rameter, but `$2[3,5]' is the entire second parameter concatenated with
499 the filename generation pattern `[3,5]'.
500
502 The positional parameters provide access to the command-line arguments
503 of a shell function, shell script, or the shell itself; see the section
504 `Invocation', and also the section `Functions'. The parameter n, where
505 n is a number, is the nth positional parameter. The parameter `$0' is
506 a special case, see the section `Parameters Set By The Shell'.
507 The parameters *, @ and argv are arrays containing all the positional
509 parameters; thus `$argv[n]', etc., is equivalent to simply `$n'. Note
510 that the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT apply to these arrays
511 as well, so with either of those options set, `${argv[0]}' is equiva‐
512 lent to `$1' and so on.
513 Positional parameters may be changed after the shell or function starts
515 by using the set builtin, by assigning to the argv array, or by direct
516 assignment of the form `n=value' where n is the number of the posi‐
517 tional parameter to be changed. This also creates (with empty values)
518 any of the positions from 1 to n that do not already have values. Note
519 that, because the positional parameters form an array, an array assign‐
520 ment of the form `n=(value ...)' is allowed, and has the effect of
521 shifting all the values at positions greater than n by as many posi‐
522 tions as necessary to accommodate the new values.
523
525 Shell function executions delimit scopes for shell parameters. (Param‐
526 eters are dynamically scoped.) The typeset builtin, and its alterna‐
527 tive forms declare, integer, local and readonly (but not export), can
528 be used to declare a parameter as being local to the innermost scope.
529 When a parameter is read or assigned to, the innermost existing parame‐
531 ter of that name is used. (That is, the local parameter hides any
532 less-local parameter.) However, assigning to a non-existent parameter,
533 or declaring a new parameter with export, causes it to be created in
534 the outermost scope.
535 Local parameters disappear when their scope ends. unset can be used to
537 delete a parameter while it is still in scope; any outer parameter of
538 the same name remains hidden.
539 Special parameters may also be made local; they retain their special
541 attributes unless either the existing or the newly-created parameter
542 has the -h (hide) attribute. This may have unexpected effects: there
543 is no default value, so if there is no assignment at the point the
544 variable is made local, it will be set to an empty value (or zero in
545 the case of integers). The following:
546 typeset PATH=/new/directory:$PATH
548 is valid for temporarily allowing the shell or programmes called from
550 it to find the programs in /new/directory inside a function.
551 Note that the restriction in older versions of zsh that local parame‐
553 ters were never exported has been removed.
554
556 In the parameter lists that follow, the mark `<S>' indicates that the
557 parameter is special. `<Z>' indicates that the parameter does not ex‐
558 ist when the shell initializes in sh or ksh emulation mode.
559 The parameters `!', `#', `*', `-', `?', `@', `$', `ARGC', `HISTCMD',
561 `LINENO', `PPID', `status', `TTYIDLE', `zsh_eval_context',
562 `ZSH_EVAL_CONTEXT', and `ZSH_SUBSHELL' are read-only and thus cannot be
563 restored by the user, so they are not output by `typeset -p'. This
564 also applies to many read-only parameters loaded from modules.
565 The following parameters are automatically set by the shell:
567 ! <S> The process ID of the last command started in the background
569 with &, put into the background with the bg builtin, or spawned
570 with coproc.
571 # <S> The number of positional parameters in decimal. Note that some
573 confusion may occur with the syntax $#param which substitutes
574 the length of param. Use ${#} to resolve ambiguities. In par‐
575 ticular, the sequence `$#-...' in an arithmetic expression is
576 interpreted as the length of the parameter -, q.v.
577 ARGC <S> <Z>
579 Same as #.
580 $ <S> The process ID of this shell, set when the shell initializes.
582 Processes forked from the shell without executing a new program,
583 such as command substitutions and commands grouped with (...),
584 are subshells that duplicate the current shell, and thus substi‐
585 tute the same value for $$ as their parent shell.
586 - <S> Flags supplied to the shell on invocation or by the set or se‐
588 topt commands.
589 * <S> An array containing the positional parameters.
591 argv <S> <Z>
593 Same as *. Assigning to argv changes the local positional pa‐
594 rameters, but argv is not itself a local parameter. Deleting
595 argv with unset in any function deletes it everywhere, although
596 only the innermost positional parameter array is deleted (so *
597 and @ in other scopes are not affected).
598 @ <S> Same as argv[@], even when argv is not set.
600 ? <S> The exit status returned by the last command.
602 0 <S> The name used to invoke the current shell, or as set by the -c
604 command line option upon invocation. If the FUNCTION_ARGZERO
605 option is set, $0 is set upon entry to a shell function to the
606 name of the function, and upon entry to a sourced script to the
607 name of the script, and reset to its previous value when the
608 function or script returns.
609 status <S> <Z>
611 Same as ?.
612 pipestatus <S> <Z>
614 An array containing the exit statuses returned by all commands
615 in the last pipeline.
616 _ <S> The last argument of the previous command. Also, this parameter
618 is set in the environment of every command executed to the full
619 pathname of the command.
620 CPUTYPE
622 The machine type (microprocessor class or machine model), as de‐
623 termined at run time.
624 EGID <S>
626 The effective group ID of the shell process. If you have suffi‐
627 cient privileges, you may change the effective group ID of the
628 shell process by assigning to this parameter. Also (assuming
629 sufficient privileges), you may start a single command with a
630 different effective group ID by `(EGID=gid; command)'
631 If this is made local, it is not implicitly set to 0, but may be
633 explicitly set locally.
634 EUID <S>
636 The effective user ID of the shell process. If you have suffi‐
637 cient privileges, you may change the effective user ID of the
638 shell process by assigning to this parameter. Also (assuming
639 sufficient privileges), you may start a single command with a
640 different effective user ID by `(EUID=uid; command)'
641 If this is made local, it is not implicitly set to 0, but may be
643 explicitly set locally.
644 ERRNO <S>
646 The value of errno (see errno(3)) as set by the most recently
647 failed system call. This value is system dependent and is in‐
648 tended for debugging purposes. It is also useful with the
649 zsh/system module which allows the number to be turned into a
650 name or message.
651 To use this parameter, it must first be assigned a value (typi‐
653 cally 0 (zero)). It is initially unset for scripting compati‐
654 bility.
655 FUNCNEST <S>
657 Integer. If greater than or equal to zero, the maximum nesting
658 depth of shell functions. When it is exceeded, an error is
659 raised at the point where a function is called. The default
660 value is determined when the shell is configured, but is typi‐
661 cally 500. Increasing the value increases the danger of a run‐
662 away function recursion causing the shell to crash. Setting a
663 negative value turns off the check.
664 GID <S>
666 The real group ID of the shell process. If you have sufficient
667 privileges, you may change the group ID of the shell process by
668 assigning to this parameter. Also (assuming sufficient privi‐
669 leges), you may start a single command under a different group
670 ID by `(GID=gid; command)'
671 If this is made local, it is not implicitly set to 0, but may be
673 explicitly set locally.
674 HISTCMD
676 The current history event number in an interactive shell, in
677 other words the event number for the command that caused
678 $HISTCMD to be read. If the current history event modifies the
679 history, HISTCMD changes to the new maximum history event num‐
680 ber.
681 HOST The current hostname.
683 LINENO <S>
685 The line number of the current line within the current script,
686 sourced file, or shell function being executed, whichever was
687 started most recently. Note that in the case of shell functions
688 the line number refers to the function as it appeared in the
689 original definition, not necessarily as displayed by the func‐
690 tions builtin.
691 LOGNAME
693 If the corresponding variable is not set in the environment of
694 the shell, it is initialized to the login name corresponding to
695 the current login session. This parameter is exported by default
696 but this can be disabled using the typeset builtin. The value
697 is set to the string returned by the getlogin(3) system call if
698 that is available.
699 MACHTYPE
701 The machine type (microprocessor class or machine model), as de‐
702 termined at compile time.
703 OLDPWD The previous working directory. This is set when the shell ini‐
705 tializes and whenever the directory changes.
706 OPTARG <S>
708 The value of the last option argument processed by the getopts
709 command.
710 OPTIND <S>
712 The index of the last option argument processed by the getopts
713 command.
714 OSTYPE The operating system, as determined at compile time.
716 PPID <S>
718 The process ID of the parent of the shell, set when the shell
719 initializes. As with $$, the value does not change in subshells
720 created as a duplicate of the current shell.
721 PWD The present working directory. This is set when the shell ini‐
723 tializes and whenever the directory changes.
724 RANDOM <S>
726 A pseudo-random integer from 0 to 32767, newly generated each
727 time this parameter is referenced. The random number generator
728 can be seeded by assigning a numeric value to RANDOM.
729 The values of RANDOM form an intentionally-repeatable
731 pseudo-random sequence; subshells that reference RANDOM will re‐
732 sult in identical pseudo-random values unless the value of RAN‐
733 DOM is referenced or seeded in the parent shell in between sub‐
734 shell invocations.
735 SECONDS <S>
737 The number of seconds since shell invocation. If this parameter
738 is assigned a value, then the value returned upon reference will
739 be the value that was assigned plus the number of seconds since
740 the assignment.
741 Unlike other special parameters, the type of the SECONDS parame‐
743 ter can be changed using the typeset command. The type may be
744 changed only to one of the floating point types or back to inte‐
745 ger. For example, `typeset -F SECONDS' causes the value to be
746 reported as a floating point number. The value is available to
747 microsecond accuracy, although the shell may show more or fewer
748 digits depending on the use of typeset. See the documentation
749 for the builtin typeset in zshbuiltins(1) for more details.
750 SHLVL <S>
752 Incremented by one each time a new shell is started.
753 signals
755 An array containing the names of the signals. Note that with
756 the standard zsh numbering of array indices, where the first el‐
757 ement has index 1, the signals are offset by 1 from the signal
758 number used by the operating system. For example, on typical
759 Unix-like systems HUP is signal number 1, but is referred to as
760 $signals[2]. This is because of EXIT at position 1 in the ar‐
761 ray, which is used internally by zsh but is not known to the op‐
762 erating system.
763 TRY_BLOCK_ERROR <S>
765 In an always block, indicates whether the preceding list of code
766 caused an error. The value is 1 to indicate an error, 0 other‐
767 wise. It may be reset, clearing the error condition. See Com‐
768 plex Commands in zshmisc(1)
769 TRY_BLOCK_INTERRUPT <S>
771 This variable works in a similar way to TRY_BLOCK_ERROR, but
772 represents the status of an interrupt from the signal SIGINT,
773 which typically comes from the keyboard when the user types ^C.
774 If set to 0, any such interrupt will be reset; otherwise, the
775 interrupt is propagated after the always block.
776 Note that it is possible that an interrupt arrives during the
778 execution of the always block; this interrupt is also propa‐
779 gated.
780 TTY The name of the tty associated with the shell, if any.
782 TTYIDLE <S>
784 The idle time of the tty associated with the shell in seconds or
785 -1 if there is no such tty.
786 UID <S>
788 The real user ID of the shell process. If you have sufficient
789 privileges, you may change the user ID of the shell by assigning
790 to this parameter. Also (assuming sufficient privileges), you
791 may start a single command under a different user ID by
792 `(UID=uid; command)'
793 If this is made local, it is not implicitly set to 0, but may be
795 explicitly set locally.
796 USERNAME <S>
798 The username corresponding to the real user ID of the shell
799 process. If you have sufficient privileges, you may change the
800 username (and also the user ID and group ID) of the shell by as‐
801 signing to this parameter. Also (assuming sufficient privi‐
802 leges), you may start a single command under a different user‐
803 name (and user ID and group ID) by `(USERNAME=username; com‐
804 mand)'
805 VENDOR The vendor, as determined at compile time.
807 zsh_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
809 An array (colon-separated list) indicating the context of shell
810 code that is being run. Each time a piece of shell code that is
811 stored within the shell is executed a string is temporarily ap‐
812 pended to the array to indicate the type of operation that is
813 being performed. Read in order the array gives an indication of
814 the stack of operations being performed with the most immediate
815 context last.
816 Note that the variable does not give information on syntactic
818 context such as pipelines or subshells. Use $ZSH_SUBSHELL to
819 detect subshells.
820 The context is one of the following:
822 cmdarg Code specified by the -c option to the command line that
823 invoked the shell.
824 cmdsubst
826 Command substitution using the `...` or $(...) construct.
827 equalsubst
829 File substitution using the =(...) construct.
830 eval Code executed by the eval builtin.
832 evalautofunc
834 Code executed with the KSH_AUTOLOAD mechanism in order to
835 define an autoloaded function.
836 fc Code from the shell history executed by the -e option to
838 the fc builtin.
839 file Lines of code being read directly from a file, for exam‐
841 ple by the source builtin.
842 filecode
844 Lines of code being read from a .zwc file instead of di‐
845 rectly from the source file.
846 globqual
848 Code executed by the e or + glob qualifier.
849 globsort
851 Code executed to order files by the o glob qualifier.
852 insubst
854 File substitution using the <(...) construct.
855 loadautofunc
857 Code read directly from a file to define an autoloaded
858 function.
859 outsubst
861 File substitution using the >(...) construct.
862 sched Code executed by the sched builtin.
864 shfunc A shell function.
866 stty Code passed to stty by the STTY environment variable.
868 Normally this is passed directly to the system's stty
869 command, so this value is unlikely to be seen in prac‐
870 tice.
871 style Code executed as part of a style retrieved by the zstyle
873 builtin from the zsh/zutil module.
874 toplevel
876 The highest execution level of a script or interactive
877 shell.
878 trap Code executed as a trap defined by the trap builtin.
880 Traps defined as functions have the context shfunc. As
881 traps are asynchronous they may have a different hierar‐
882 chy from other code.
883 zpty Code executed by the zpty builtin from the zsh/zpty mod‐
885 ule.
886 zregexparse-guard
888 Code executed as a guard by the zregexparse command from
889 the zsh/zutil module.
890 zregexparse-action
892 Code executed as an action by the zregexparse command
893 from the zsh/zutil module.
894 ZSH_ARGZERO
896 If zsh was invoked to run a script, this is the name of the
897 script. Otherwise, it is the name used to invoke the current
898 shell. This is the same as the value of $0 when the
899 POSIX_ARGZERO option is set, but is always available.
900 ZSH_EXECUTION_STRING
902 If the shell was started with the option -c, this contains the
903 argument passed to the option. Otherwise it is not set.
904 ZSH_NAME
906 Expands to the basename of the command used to invoke this in‐
907 stance of zsh.
908 ZSH_PATCHLEVEL
910 The output of `git describe --tags --long' for the zsh reposi‐
911 tory used to build the shell. This is most useful in order to
912 keep track of versions of the shell during development between
913 releases; hence most users should not use it and should instead
914 rely on $ZSH_VERSION.
915 zsh_scheduled_events
917 See the section `The zsh/sched Module' in zshmodules(1).
918 ZSH_SCRIPT
920 If zsh was invoked to run a script, this is the name of the
921 script, otherwise it is unset.
922 ZSH_SUBSHELL
924 Readonly integer. Initially zero, incremented each time the
925 shell forks to create a subshell for executing code. Hence
926 `(print $ZSH_SUBSHELL)' and `print $(print $ZSH_SUBSHELL)' out‐
927 put 1, while `( (print $ZSH_SUBSHELL) )' outputs 2.
928 ZSH_VERSION
930 The version number of the release of zsh.
931
933 The following parameters are used by the shell. Again, `<S>' indicates
934 that the parameter is special and `<Z>' indicates that the parameter
935 does not exist when the shell initializes in sh or ksh emulation mode.
936 In cases where there are two parameters with an upper- and lowercase
938 form of the same name, such as path and PATH, the lowercase form is an
939 array and the uppercase form is a scalar with the elements of the array
940 joined together by colons. These are similar to tied parameters cre‐
941 ated via `typeset -T'. The normal use for the colon-separated form is
942 for exporting to the environment, while the array form is easier to ma‐
943 nipulate within the shell. Note that unsetting either of the pair will
944 unset the other; they retain their special properties when recreated,
945 and recreating one of the pair will recreate the other.
946 ARGV0 If exported, its value is used as the argv[0] of external com‐
948 mands. Usually used in constructs like `ARGV0=emacs nethack'.
949 BAUD The rate in bits per second at which data reaches the terminal.
951 The line editor will use this value in order to compensate for a
952 slow terminal by delaying updates to the display until neces‐
953 sary. If the parameter is unset or the value is zero the com‐
954 pensation mechanism is turned off. The parameter is not set by
955 default.
956 This parameter may be profitably set in some circumstances, e.g.
958 for slow modems dialing into a communications server, or on a
959 slow wide area network. It should be set to the baud rate of
960 the slowest part of the link for best performance.
961 cdpath <S> <Z> (CDPATH <S>)
963 An array (colon-separated list) of directories specifying the
964 search path for the cd command.
965 COLUMNS <S>
967 The number of columns for this terminal session. Used for
968 printing select lists and for the line editor.
969 CORRECT_IGNORE
971 If set, is treated as a pattern during spelling correction. Any
972 potential correction that matches the pattern is ignored. For
973 example, if the value is `_*' then completion functions (which,
974 by convention, have names beginning with `_') will never be of‐
975 fered as spelling corrections. The pattern does not apply to
976 the correction of file names, as applied by the CORRECT_ALL op‐
977 tion (so with the example just given files beginning with `_' in
978 the current directory would still be completed).
979 CORRECT_IGNORE_FILE
981 If set, is treated as a pattern during spelling correction of
982 file names. Any file name that matches the pattern is never of‐
983 fered as a correction. For example, if the value is `.*' then
984 dot file names will never be offered as spelling corrections.
985 This is useful with the CORRECT_ALL option.
986 DIRSTACKSIZE
988 The maximum size of the directory stack, by default there is no
989 limit. If the stack gets larger than this, it will be truncated
990 automatically. This is useful with the AUTO_PUSHD option.
991 ENV If the ENV environment variable is set when zsh is invoked as sh
993 or ksh, $ENV is sourced after the profile scripts. The value of
994 ENV is subjected to parameter expansion, command substitution,
995 and arithmetic expansion before being interpreted as a pathname.
996 Note that ENV is not used unless the shell is interactive and
997 zsh is emulating sh or ksh.
998 FCEDIT The default editor for the fc builtin. If FCEDIT is not set,
1000 the parameter EDITOR is used; if that is not set either, a
1001 builtin default, usually vi, is used.
1002 fignore <S> <Z> (FIGNORE <S>)
1004 An array (colon separated list) containing the suffixes of files
1005 to be ignored during filename completion. However, if comple‐
1006 tion only generates files with suffixes in this list, then these
1007 files are completed anyway.
1008 fpath <S> <Z> (FPATH <S>)
1010 An array (colon separated list) of directories specifying the
1011 search path for function definitions. This path is searched
1012 when a function with the -u attribute is referenced. If an exe‐
1013 cutable file is found, then it is read and executed in the cur‐
1014 rent environment.
1015 histchars <S>
1017 Three characters used by the shell's history and lexical analy‐
1018 sis mechanism. The first character signals the start of a his‐
1019 tory expansion (default `!'). The second character signals the
1020 start of a quick history substitution (default `^'). The third
1021 character is the comment character (default `#').
1022 The characters must be in the ASCII character set; any attempt
1024 to set histchars to characters with a locale-dependent meaning
1025 will be rejected with an error message.
1026 HISTCHARS <S> <Z>
1028 Same as histchars. (Deprecated.)
1029 HISTFILE
1031 The file to save the history in when an interactive shell exits.
1032 If unset, the history is not saved.
1033 HISTORY_IGNORE
1035 If set, is treated as a pattern at the time history files are
1036 written. Any potential history entry that matches the pattern
1037 is skipped. For example, if the value is `fc *' then commands
1038 that invoke the interactive history editor are never written to
1039 the history file.
1040 Note that HISTORY_IGNORE defines a single pattern: to specify
1042 alternatives use the `(first|second|...)' syntax.
1043 Compare the HIST_NO_STORE option or the zshaddhistory hook, ei‐
1045 ther of which would prevent such commands from being added to
1046 the interactive history at all. If you wish to use HISTORY_IG‐
1047 NORE to stop history being added in the first place, you can de‐
1048 fine the following hook:
1049 zshaddhistory() {
1051 emulate -L zsh
1052 ## uncomment if HISTORY_IGNORE
1053 ## should use EXTENDED_GLOB syntax
1054 # setopt extendedglob
1055 [[ $1 != ${~HISTORY_IGNORE} ]]
1056 }
1057 HISTSIZE <S>
1059 The maximum number of events stored in the internal history
1060 list. If you use the HIST_EXPIRE_DUPS_FIRST option, setting
1061 this value larger than the SAVEHIST size will give you the dif‐
1062 ference as a cushion for saving duplicated history events.
1063 If this is made local, it is not implicitly set to 0, but may be
1065 explicitly set locally.
1066 HOME <S>
1068 The default argument for the cd command. This is not set auto‐
1069 matically by the shell in sh, ksh or csh emulation, but it is
1070 typically present in the environment anyway, and if it becomes
1071 set it has its usual special behaviour.
1072 IFS <S>
1074 Internal field separators (by default space, tab, newline and
1075 NUL), that are used to separate words which result from command
1076 or parameter expansion and words read by the read builtin. Any
1077 characters from the set space, tab and newline that appear in
1078 the IFS are called IFS white space. One or more IFS white space
1079 characters or one non-IFS white space character together with
1080 any adjacent IFS white space character delimit a field. If an
1081 IFS white space character appears twice consecutively in the
1082 IFS, this character is treated as if it were not an IFS white
1083 space character.
1084 If the parameter is unset, the default is used. Note this has a
1086 different effect from setting the parameter to an empty string.
1087 KEYBOARD_HACK
1089 This variable defines a character to be removed from the end of
1090 the command line before interpreting it (interactive shells
1091 only). It is intended to fix the problem with keys placed annoy‐
1092 ingly close to return and replaces the SUNKEYBOARDHACK option
1093 which did this for backquotes only. Should the chosen character
1094 be one of singlequote, doublequote or backquote, there must also
1095 be an odd number of them on the command line for the last one to
1096 be removed.
1097 For backward compatibility, if the SUNKEYBOARDHACK option is ex‐
1099 plicitly set, the value of KEYBOARD_HACK reverts to backquote.
1100 If the option is explicitly unset, this variable is set to
1101 empty.
1102 KEYTIMEOUT
1104 The time the shell waits, in hundredths of seconds, for another
1105 key to be pressed when reading bound multi-character sequences.
1106 LANG <S>
1108 This variable determines the locale category for any category
1109 not specifically selected via a variable starting with `LC_'.
1110 LC_ALL <S>
1112 This variable overrides the value of the `LANG' variable and the
1113 value of any of the other variables starting with `LC_'.
1114 LC_COLLATE <S>
1116 This variable determines the locale category for character col‐
1117 lation information within ranges in glob brackets and for sort‐
1118 ing.
1119 LC_CTYPE <S>
1121 This variable determines the locale category for character han‐
1122 dling functions. If the MULTIBYTE option is in effect this
1123 variable or LANG should contain a value that reflects the char‐
1124 acter set in use, even if it is a single-byte character set, un‐
1125 less only the 7-bit subset (ASCII) is used. For example, if the
1126 character set is ISO-8859-1, a suitable value might be
1127 en_US.iso88591 (certain Linux distributions) or en_US.ISO8859-1
1128 (MacOS).
1129 LC_MESSAGES <S>
1131 This variable determines the language in which messages should
1132 be written. Note that zsh does not use message catalogs.
1133 LC_NUMERIC <S>
1135 This variable affects the decimal point character and thousands
1136 separator character for the formatted input/output functions and
1137 string conversion functions. Note that zsh ignores this setting
1138 when parsing floating point mathematical expressions.
1139 LC_TIME <S>
1141 This variable determines the locale category for date and time
1142 formatting in prompt escape sequences.
1143 LINES <S>
1145 The number of lines for this terminal session. Used for print‐
1146 ing select lists and for the line editor.
1147 LISTMAX
1149 In the line editor, the number of matches to list without asking
1150 first. If the value is negative, the list will be shown if it
1151 spans at most as many lines as given by the absolute value. If
1152 set to zero, the shell asks only if the top of the listing would
1153 scroll off the screen.
1154 MAIL If this parameter is set and mailpath is not set, the shell
1156 looks for mail in the specified file.
1157 MAILCHECK
1159 The interval in seconds between checks for new mail.
1160 mailpath <S> <Z> (MAILPATH <S>)
1162 An array (colon-separated list) of filenames to check for new
1163 mail. Each filename can be followed by a `?' and a message that
1164 will be printed. The message will undergo parameter expansion,
1165 command substitution and arithmetic expansion with the variable
1166 $_ defined as the name of the file that has changed. The de‐
1167 fault message is `You have new mail'. If an element is a direc‐
1168 tory instead of a file the shell will recursively check every
1169 file in every subdirectory of the element.
1170 manpath <S> <Z> (MANPATH <S> <Z>)
1172 An array (colon-separated list) whose value is not used by the
1173 shell. The manpath array can be useful, however, since setting
1174 it also sets MANPATH, and vice versa.
1175 match
1177 mbegin
1178 mend Arrays set by the shell when the b globbing flag is used in pat‐
1179 tern matches. See the subsection Globbing flags in the documen‐
1180 tation for Filename Generation in zshexpn(1).
1181 MATCH
1183 MBEGIN
1184 MEND Set by the shell when the m globbing flag is used in pattern
1185 matches. See the subsection Globbing flags in the documentation
1186 for Filename Generation in zshexpn(1).
1187 module_path <S> <Z> (MODULE_PATH <S>)
1189 An array (colon-separated list) of directories that zmodload
1190 searches for dynamically loadable modules. This is initialized
1191 to a standard pathname, usually `/usr/local/lib/zsh/$ZSH_VER‐
1192 SION'. (The `/usr/local/lib' part varies from installation to
1193 installation.) For security reasons, any value set in the envi‐
1194 ronment when the shell is started will be ignored.
1195 These parameters only exist if the installation supports dynamic
1197 module loading.
1198 NULLCMD <S>
1200 The command name to assume if a redirection is specified with no
1201 command. Defaults to cat. For sh/ksh behavior, change this to
1202 :. For csh-like behavior, unset this parameter; the shell will
1203 print an error message if null commands are entered.
1204 path <S> <Z> (PATH <S>)
1206 An array (colon-separated list) of directories to search for
1207 commands. When this parameter is set, each directory is scanned
1208 and all files found are put in a hash table.
1209 POSTEDIT <S>
1211 This string is output whenever the line editor exits. It usu‐
1212 ally contains termcap strings to reset the terminal.
1213 PROMPT <S> <Z>
1215 PROMPT2 <S> <Z>
1216 PROMPT3 <S> <Z>
1217 PROMPT4 <S> <Z>
1218 Same as PS1, PS2, PS3 and PS4, respectively.
1219 prompt <S> <Z>
1221 Same as PS1.
1222 PROMPT_EOL_MARK
1224 When the PROMPT_CR and PROMPT_SP options are set, the
1225 PROMPT_EOL_MARK parameter can be used to customize how the end
1226 of partial lines are shown. This parameter undergoes prompt ex‐
1227 pansion, with the PROMPT_PERCENT option set. If not set, the
1228 default behavior is equivalent to the value `%B%S%#%s%b'.
1229 PS1 <S>
1231 The primary prompt string, printed before a command is read. It
1232 undergoes a special form of expansion before being displayed;
1233 see EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The default is
1234 `%m%# '.
1235 PS2 <S>
1237 The secondary prompt, printed when the shell needs more informa‐
1238 tion to complete a command. It is expanded in the same way as
1239 PS1. The default is `%_> ', which displays any shell constructs
1240 or quotation marks which are currently being processed.
1241 PS3 <S>
1243 Selection prompt used within a select loop. It is expanded in
1244 the same way as PS1. The default is `?# '.
1245 PS4 <S>
1247 The execution trace prompt. Default is `+%N:%i> ', which dis‐
1248 plays the name of the current shell structure and the line num‐
1249 ber within it. In sh or ksh emulation, the default is `+ '.
1250 psvar <S> <Z> (PSVAR <S>)
1252 An array (colon-separated list) whose elements can be used in
1253 PROMPT strings. Setting psvar also sets PSVAR, and vice versa.
1254 READNULLCMD <S>
1256 The command name to assume if a single input redirection is
1257 specified with no command. Defaults to more.
1258 REPORTMEMORY
1260 If nonnegative, commands whose maximum resident set size
1261 (roughly speaking, main memory usage) in kilobytes is greater
1262 than this value have timing statistics reported. The format
1263 used to output statistics is the value of the TIMEFMT parameter,
1264 which is the same as for the REPORTTIME variable and the time
1265 builtin; note that by default this does not output memory usage.
1266 Appending " max RSS %M" to the value of TIMEFMT causes it to
1267 output the value that triggered the report. If REPORTTIME is
1268 also in use, at most a single report is printed for both trig‐
1269 gers. This feature requires the getrusage() system call, com‐
1270 monly supported by modern Unix-like systems.
1271 REPORTTIME
1273 If nonnegative, commands whose combined user and system execu‐
1274 tion times (measured in seconds) are greater than this value
1275 have timing statistics printed for them. Output is suppressed
1276 for commands executed within the line editor, including comple‐
1277 tion; commands explicitly marked with the time keyword still
1278 cause the summary to be printed in this case.
1279 REPLY This parameter is reserved by convention to pass string values
1281 between shell scripts and shell builtins in situations where a
1282 function call or redirection are impossible or undesirable. The
1283 read builtin and the select complex command may set REPLY, and
1284 filename generation both sets and examines its value when evalu‐
1285 ating certain expressions. Some modules also employ REPLY for
1286 similar purposes.
1287 reply As REPLY, but for array values rather than strings.
1289 RPROMPT <S>
1291 RPS1 <S>
1292 This prompt is displayed on the right-hand side of the screen
1293 when the primary prompt is being displayed on the left. This
1294 does not work if the SINGLE_LINE_ZLE option is set. It is ex‐
1295 panded in the same way as PS1.
1296 RPROMPT2 <S>
1298 RPS2 <S>
1299 This prompt is displayed on the right-hand side of the screen
1300 when the secondary prompt is being displayed on the left. This
1301 does not work if the SINGLE_LINE_ZLE option is set. It is ex‐
1302 panded in the same way as PS2.
1303 SAVEHIST
1305 The maximum number of history events to save in the history
1306 file.
1307 If this is made local, it is not implicitly set to 0, but may be
1309 explicitly set locally.
1310 SPROMPT <S>
1312 The prompt used for spelling correction. The sequence `%R' ex‐
1313 pands to the string which presumably needs spelling correction,
1314 and `%r' expands to the proposed correction. All other prompt
1315 escapes are also allowed.
1316 The actions available at the prompt are [nyae]:
1318 n (`no') (default)
1319 Discard the correction and run the command.
1320 y (`yes')
1321 Make the correction and run the command.
1322 a (`abort')
1323 Discard the entire command line without running it.
1324 e (`edit')
1325 Resume editing the command line.
1326 STTY If this parameter is set in a command's environment, the shell
1328 runs the stty command with the value of this parameter as argu‐
1329 ments in order to set up the terminal before executing the com‐
1330 mand. The modes apply only to the command, and are reset when it
1331 finishes or is suspended. If the command is suspended and con‐
1332 tinued later with the fg or wait builtins it will see the modes
1333 specified by STTY, as if it were not suspended. This (inten‐
1334 tionally) does not apply if the command is continued via `kill
1335 -CONT'. STTY is ignored if the command is run in the back‐
1336 ground, or if it is in the environment of the shell but not ex‐
1337 plicitly assigned to in the input line. This avoids running stty
1338 at every external command by accidentally exporting it. Also
1339 note that STTY should not be used for window size specifica‐
1340 tions; these will not be local to the command.
1341 If the parameter is set and empty, all of the above applies ex‐
1343 cept that stty is not run. This can be useful as a way to freeze
1344 the tty around a single command, blocking its changes to tty
1345 settings, similar to the ttyctl builtin.
1346 TERM <S>
1348 The type of terminal in use. This is used when looking up term‐
1349 cap sequences. An assignment to TERM causes zsh to re-initial‐
1350 ize the terminal, even if the value does not change (e.g.,
1351 `TERM=$TERM'). It is necessary to make such an assignment upon
1352 any change to the terminal definition database or terminal type
1353 in order for the new settings to take effect.
1354 TERMINFO <S>
1356 A reference to your terminfo database, used by the `terminfo'
1357 library when the system has it; see terminfo(5). If set, this
1358 causes the shell to reinitialise the terminal, making the work‐
1359 around `TERM=$TERM' unnecessary.
1360 TERMINFO_DIRS <S>
1362 A colon-seprarated list of terminfo databases, used by the `ter‐
1363 minfo' library when the system has it; see terminfo(5). This
1364 variable is only used by certain terminal libraries, in particu‐
1365 lar ncurses; see terminfo(5) to check support on your system.
1366 If set, this causes the shell to reinitialise the terminal, mak‐
1367 ing the workaround `TERM=$TERM' unnecessary. Note that unlike
1368 other colon-separated arrays this is not tied to a zsh array.
1369 TIMEFMT
1371 The format of process time reports with the time keyword. The
1372 default is `%J %U user %S system %P cpu %*E total'. Recognizes
1373 the following escape sequences, although not all may be avail‐
1374 able on all systems, and some that are available may not be use‐
1375 ful:
1376 %% A `%'.
1378 %U CPU seconds spent in user mode.
1379 %S CPU seconds spent in kernel mode.
1380 %E Elapsed time in seconds.
1381 %P The CPU percentage, computed as 100*(%U+%S)/%E.
1382 %W Number of times the process was swapped.
1383 %X The average amount in (shared) text space used in kilo‐
1384 bytes.
1385 %D The average amount in (unshared) data/stack space used in
1386 kilobytes.
1387 %K The total space used (%X+%D) in kilobytes.
1388 %M The maximum memory the process had in use at any time in
1389 kilobytes.
1390 %F The number of major page faults (page needed to be
1391 brought from disk).
1392 %R The number of minor page faults.
1393 %I The number of input operations.
1394 %O The number of output operations.
1395 %r The number of socket messages received.
1396 %s The number of socket messages sent.
1397 %k The number of signals received.
1398 %w Number of voluntary context switches (waits).
1399 %c Number of involuntary context switches.
1400 %J The name of this job.
1401 A star may be inserted between the percent sign and flags print‐
1403 ing time (e.g., `%*E'); this causes the time to be printed in
1404 `hh:mm:ss.ttt' format (hours and minutes are only printed if
1405 they are not zero). Alternatively, `m' or `u' may be used
1406 (e.g., `%mE') to produce time output in milliseconds or mi‐
1407 croseconds, respectively.
1408 TMOUT If this parameter is nonzero, the shell will receive an ALRM
1410 signal if a command is not entered within the specified number
1411 of seconds after issuing a prompt. If there is a trap on
1412 SIGALRM, it will be executed and a new alarm is scheduled using
1413 the value of the TMOUT parameter after executing the trap. If
1414 no trap is set, and the idle time of the terminal is not less
1415 than the value of the TMOUT parameter, zsh terminates. Other‐
1416 wise a new alarm is scheduled to TMOUT seconds after the last
1417 keypress.
1418 TMPPREFIX
1420 A pathname prefix which the shell will use for all temporary
1421 files. Note that this should include an initial part for the
1422 file name as well as any directory names. The default is
1423 `/tmp/zsh'.
1424 TMPSUFFIX
1426 A filename suffix which the shell will use for temporary files
1427 created by process substitutions (e.g., `=(list)'). Note that
1428 the value should include a leading dot `.' if intended to be in‐
1429 terpreted as a file extension. The default is not to append any
1430 suffix, thus this parameter should be assigned only when needed
1431 and then unset again.
1432 WORDCHARS <S>
1434 A list of non-alphanumeric characters considered part of a word
1435 by the line editor.
1436 ZBEEP If set, this gives a string of characters, which can use all the
1438 same codes as the bindkey command as described in the zsh/zle
1439 module entry in zshmodules(1), that will be output to the termi‐
1440 nal instead of beeping. This may have a visible instead of an
1441 audible effect; for example, the string `\e[?5h\e[?5l' on a
1442 vt100 or xterm will have the effect of flashing reverse video on
1443 and off (if you usually use reverse video, you should use the
1444 string `\e[?5l\e[?5h' instead). This takes precedence over the
1445 NOBEEP option.
1446 ZDOTDIR
1448 The directory to search for shell startup files (.zshrc, etc),
1449 if not $HOME.
1450 zle_bracketed_paste
1452 Many terminal emulators have a feature that allows applications
1453 to identify when text is pasted into the terminal rather than
1454 being typed normally. For ZLE, this means that special charac‐
1455 ters such as tabs and newlines can be inserted instead of invok‐
1456 ing editor commands. Furthermore, pasted text forms a single
1457 undo event and if the region is active, pasted text will replace
1458 the region.
1459 This two-element array contains the terminal escape sequences
1461 for enabling and disabling the feature. These escape sequences
1462 are used to enable bracketed paste when ZLE is active and dis‐
1463 able it at other times. Unsetting the parameter has the effect
1464 of ensuring that bracketed paste remains disabled.
1465 zle_highlight
1467 An array describing contexts in which ZLE should highlight the
1468 input text. See Character Highlighting in zshzle(1).
1469 ZLE_LINE_ABORTED
1471 This parameter is set by the line editor when an error occurs.
1472 It contains the line that was being edited at the point of the
1473 error. `print -zr -- $ZLE_LINE_ABORTED' can be used to recover
1474 the line. Only the most recent line of this kind is remembered.
1475 ZLE_REMOVE_SUFFIX_CHARS
1477 ZLE_SPACE_SUFFIX_CHARS
1478 These parameters are used by the line editor. In certain cir‐
1479 cumstances suffixes (typically space or slash) added by the com‐
1480 pletion system will be removed automatically, either because the
1481 next editing command was not an insertable character, or because
1482 the character was marked as requiring the suffix to be removed.
1483 These variables can contain the sets of characters that will
1485 cause the suffix to be removed. If ZLE_REMOVE_SUFFIX_CHARS is
1486 set, those characters will cause the suffix to be removed; if
1487 ZLE_SPACE_SUFFIX_CHARS is set, those characters will cause the
1488 suffix to be removed and replaced by a space.
1489 If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is
1491 equivalent to:
1492 ZLE_REMOVE_SUFFIX_CHARS=$' \t\n;&|'
1494 If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no characters
1496 have this behaviour. ZLE_SPACE_SUFFIX_CHARS takes precedence,
1497 so that the following:
1498 ZLE_SPACE_SUFFIX_CHARS=$'&|'
1500 causes the characters `&' and `|' to remove the suffix but to
1502 replace it with a space.
1503 To illustrate the difference, suppose that the option AUTO_RE‐
1505 MOVE_SLASH is in effect and the directory DIR has just been com‐
1506 pleted, with an appended /, following which the user types `&'.
1507 The default result is `DIR&'. With ZLE_REMOVE_SUFFIX_CHARS set
1508 but without including `&' the result is `DIR/&'. With
1509 ZLE_SPACE_SUFFIX_CHARS set to include `&' the result is `DIR &'.
1510 Note that certain completions may provide their own suffix re‐
1512 moval or replacement behaviour which overrides the values de‐
1513 scribed here. See the completion system documentation in zsh‐
1514 compsys(1).
1515 ZLE_RPROMPT_INDENT <S>
1517 If set, used to give the indentation between the right hand side
1518 of the right prompt in the line editor as given by RPS1 or
1519 RPROMPT and the right hand side of the screen. If not set, the
1520 value 1 is used.
1521 Typically this will be used to set the value to 0 so that the
1523 prompt appears flush with the right hand side of the screen.
1524 This is not the default as many terminals do not handle this
1525 correctly, in particular when the prompt appears at the extreme
1526 bottom right of the screen. Recent virtual terminals are more
1527 likely to handle this case correctly. Some experimentation is
1528 necessary.
1529zsh 5.9 May 14, 2022 ZSHPARAM(1)