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 I Like `i', but gives the index of the last match, or all possible
348 matching keys in an associative array. On failure substitutes
349 0, or the empty string for an associative array. This flag is
350 best when testing for values or keys that do not exist.
351 k If used in a subscript on an associative array, this flag causes
353 the keys to be interpreted as patterns, and returns the value
354 for the first key found where exp is matched by the key. Note
355 this could be any such key as no ordering of associative arrays
356 is defined. This flag does not work on the left side of an as‐
357 signment to an associative array element. If used on another
358 type of parameter, this behaves like `r'.
359 K On an associative array this is like `k' but returns all values
361 where exp is matched by the keys. On other types of parameters
362 this has the same effect as `R'.
363 n:expr:
365 If combined with `r', `R', `i' or `I', makes them give the nth
366 or nth last match (if expr evaluates to n). This flag is ig‐
367 nored when the array is associative. The delimiter character :
368 is arbitrary; see above.
369 b:expr:
371 If combined with `r', `R', `i' or `I', makes them begin at the
372 nth or nth last element, word, or character (if expr evaluates
373 to n). This flag is ignored when the array is associative. The
374 delimiter character : is arbitrary; see above.
375 e This flag causes any pattern matching that would be performed on
377 the subscript to use plain string matching instead. Hence
378 `${array[(re)*]}' matches only the array element whose value is
379 *. Note that other forms of substitution such as parameter sub‐
380 stitution are not inhibited.
381 This flag can also be used to force * or @ to be interpreted as
383 a single key rather than as a reference to all values. It may
384 be used for either purpose on the left side of an assignment.
385 See Parameter Expansion Flags (zshexpn(1)) for additional ways to ma‐
387 nipulate the results of array subscripting.
388 Subscript Parsing
390 This discussion applies mainly to associative array key strings and to
391 patterns used for reverse subscripting (the `r', `R', `i', etc. flags),
392 but it may also affect parameter substitutions that appear as part of
393 an arithmetic expression in an ordinary subscript.
394 To avoid subscript parsing limitations in assignments to associative
396 array elements, use the append syntax:
397 aa+=('key with "*strange*" characters' 'value string')
399 The basic rule to remember when writing a subscript expression is that
401 all text between the opening `[' and the closing `]' is interpreted as
402 if it were in double quotes (see zshmisc(1)). However, unlike double
403 quotes which normally cannot nest, subscript expressions may appear in‐
404 side double-quoted strings or inside other subscript expressions (or
405 both!), so the rules have two important differences.
406 The first difference is that brackets (`[' and `]') must appear as bal‐
408 anced pairs in a subscript expression unless they are preceded by a
409 backslash (`\'). Therefore, within a subscript expression (and unlike
410 true double-quoting) the sequence `\[' becomes `[', and similarly `\]'
411 becomes `]'. This applies even in cases where a backslash is not nor‐
412 mally required; for example, the pattern `[^[]' (to match any character
413 other than an open bracket) should be written `[^\[]' in a reverse-sub‐
414 script pattern. However, note that `\[^\[\]' and even `\[^[]' mean the
415 same thing, because backslashes are always stripped when they appear
416 before brackets!
417 The same rule applies to parentheses (`(' and `)') and braces (`{' and
419 `}'): they must appear either in balanced pairs or preceded by a back‐
420 slash, and backslashes that protect parentheses or braces are removed
421 during parsing. This is because parameter expansions may be surrounded
422 by balanced braces, and subscript flags are introduced by balanced
423 parentheses.
424 The second difference is that a double-quote (`"') may appear as part
426 of a subscript expression without being preceded by a backslash, and
427 therefore that the two characters `\"' remain as two characters in the
428 subscript (in true double-quoting, `\"' becomes `"'). However, because
429 of the standard shell quoting rules, any double-quotes that appear must
430 occur in balanced pairs unless preceded by a backslash. This makes it
431 more difficult to write a subscript expression that contains an odd
432 number of double-quote characters, but the reason for this difference
433 is so that when a subscript expression appears inside true dou‐
434 ble-quotes, one can still write `\"' (rather than `\\\"') for `"'.
435 To use an odd number of double quotes as a key in an assignment, use
437 the typeset builtin and an enclosing pair of double quotes; to refer to
438 the value of that key, again use double quotes:
439 typeset -A aa
441 typeset "aa[one\"two\"three\"quotes]"=QQQ
442 print "$aa[one\"two\"three\"quotes]"
443 It is important to note that the quoting rules do not change when a pa‐
445 rameter expansion with a subscript is nested inside another subscript
446 expression. That is, it is not necessary to use additional backslashes
447 within the inner subscript expression; they are removed only once, from
448 the innermost subscript outwards. Parameters are also expanded from
449 the innermost subscript first, as each expansion is encountered left to
450 right in the outer expression.
451 A further complication arises from a way in which subscript parsing is
453 not different from double quote parsing. As in true double-quoting,
454 the sequences `\*', and `\@' remain as two characters when they appear
455 in a subscript expression. To use a literal `*' or `@' as an associa‐
456 tive array key, the `e' flag must be used:
457 typeset -A aa
459 aa[(e)*]=star
460 print $aa[(e)*]
461 A last detail must be considered when reverse subscripting is per‐
463 formed. Parameters appearing in the subscript expression are first ex‐
464 panded and then the complete expression is interpreted as a pattern.
465 This has two effects: first, parameters behave as if GLOB_SUBST were on
466 (and it cannot be turned off); second, backslashes are interpreted
467 twice, once when parsing the array subscript and again when parsing the
468 pattern. In a reverse subscript, it's necessary to use four back‐
469 slashes to cause a single backslash to match literally in the pattern.
470 For complex patterns, it is often easiest to assign the desired pattern
471 to a parameter and then refer to that parameter in the subscript, be‐
472 cause then the backslashes, brackets, parentheses, etc., are seen only
473 when the complete expression is converted to a pattern. To match the
474 value of a parameter literally in a reverse subscript, rather than as a
475 pattern, use `${(q)name}' (see zshexpn(1)) to quote the expanded value.
476 Note that the `k' and `K' flags are reverse subscripting for an ordi‐
478 nary array, but are not reverse subscripting for an associative array!
479 (For an associative array, the keys in the array itself are interpreted
480 as patterns by those flags; the subscript is a plain string in that
481 case.)
482 One final note, not directly related to subscripting: the numeric names
484 of positional parameters (described below) are parsed specially, so for
485 example `$2foo' is equivalent to `${2}foo'. Therefore, to use sub‐
486 script syntax to extract a substring from a positional parameter, the
487 expansion must be surrounded by braces; for example, `${2[3,5]}' evalu‐
488 ates to the third through fifth characters of the second positional pa‐
489 rameter, but `$2[3,5]' is the entire second parameter concatenated with
490 the filename generation pattern `[3,5]'.
491
493 The positional parameters provide access to the command-line arguments
494 of a shell function, shell script, or the shell itself; see the section
495 `Invocation', and also the section `Functions'. The parameter n, where
496 n is a number, is the nth positional parameter. The parameter `$0' is
497 a special case, see the section `Parameters Set By The Shell'.
498 The parameters *, @ and argv are arrays containing all the positional
500 parameters; thus `$argv[n]', etc., is equivalent to simply `$n'. Note
501 that the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT apply to these arrays
502 as well, so with either of those options set, `${argv[0]}' is equiva‐
503 lent to `$1' and so on.
504 Positional parameters may be changed after the shell or function starts
506 by using the set builtin, by assigning to the argv array, or by direct
507 assignment of the form `n=value' where n is the number of the posi‐
508 tional parameter to be changed. This also creates (with empty values)
509 any of the positions from 1 to n that do not already have values. Note
510 that, because the positional parameters form an array, an array assign‐
511 ment of the form `n=(value ...)' is allowed, and has the effect of
512 shifting all the values at positions greater than n by as many posi‐
513 tions as necessary to accommodate the new values.
514
516 Shell function executions delimit scopes for shell parameters. (Param‐
517 eters are dynamically scoped.) The typeset builtin, and its alterna‐
518 tive forms declare, integer, local and readonly (but not export), can
519 be used to declare a parameter as being local to the innermost scope.
520 When a parameter is read or assigned to, the innermost existing parame‐
522 ter of that name is used. (That is, the local parameter hides any
523 less-local parameter.) However, assigning to a non-existent parameter,
524 or declaring a new parameter with export, causes it to be created in
525 the outermost scope.
526 Local parameters disappear when their scope ends. unset can be used to
528 delete a parameter while it is still in scope; any outer parameter of
529 the same name remains hidden.
530 Special parameters may also be made local; they retain their special
532 attributes unless either the existing or the newly-created parameter
533 has the -h (hide) attribute. This may have unexpected effects: there
534 is no default value, so if there is no assignment at the point the
535 variable is made local, it will be set to an empty value (or zero in
536 the case of integers). The following:
537 typeset PATH=/new/directory:$PATH
539 is valid for temporarily allowing the shell or programmes called from
541 it to find the programs in /new/directory inside a function.
542 Note that the restriction in older versions of zsh that local parame‐
544 ters were never exported has been removed.
545
547 In the parameter lists that follow, the mark `<S>' indicates that the
548 parameter is special. `<Z>' indicates that the parameter does not ex‐
549 ist when the shell initializes in sh or ksh emulation mode.
550 The following parameters are automatically set by the shell:
552 ! <S> The process ID of the last command started in the background
554 with &, put into the background with the bg builtin, or spawned
555 with coproc.
556 # <S> The number of positional parameters in decimal. Note that some
558 confusion may occur with the syntax $#param which substitutes
559 the length of param. Use ${#} to resolve ambiguities. In par‐
560 ticular, the sequence `$#-...' in an arithmetic expression is
561 interpreted as the length of the parameter -, q.v.
562 ARGC <S> <Z>
564 Same as #.
565 $ <S> The process ID of this shell. Note that this indicates the
567 original shell started by invoking zsh; all processes forked
568 from the shells without executing a new program, such as sub‐
569 shells started by (...), substitute the same value.
570 - <S> Flags supplied to the shell on invocation or by the set or se‐
572 topt commands.
573 * <S> An array containing the positional parameters.
575 argv <S> <Z>
577 Same as *. Assigning to argv changes the local positional pa‐
578 rameters, but argv is not itself a local parameter. Deleting
579 argv with unset in any function deletes it everywhere, although
580 only the innermost positional parameter array is deleted (so *
581 and @ in other scopes are not affected).
582 @ <S> Same as argv[@], even when argv is not set.
584 ? <S> The exit status returned by the last command.
586 0 <S> The name used to invoke the current shell, or as set by the -c
588 command line option upon invocation. If the FUNCTION_ARGZERO
589 option is set, $0 is set upon entry to a shell function to the
590 name of the function, and upon entry to a sourced script to the
591 name of the script, and reset to its previous value when the
592 function or script returns.
593 status <S> <Z>
595 Same as ?.
596 pipestatus <S> <Z>
598 An array containing the exit statuses returned by all commands
599 in the last pipeline.
600 _ <S> The last argument of the previous command. Also, this parameter
602 is set in the environment of every command executed to the full
603 pathname of the command.
604 CPUTYPE
606 The machine type (microprocessor class or machine model), as de‐
607 termined at run time.
608 EGID <S>
610 The effective group ID of the shell process. If you have suffi‐
611 cient privileges, you may change the effective group ID of the
612 shell process by assigning to this parameter. Also (assuming
613 sufficient privileges), you may start a single command with a
614 different effective group ID by `(EGID=gid; command)'
615 If this is made local, it is not implicitly set to 0, but may be
617 explicitly set locally.
618 EUID <S>
620 The effective user ID of the shell process. If you have suffi‐
621 cient privileges, you may change the effective user ID of the
622 shell process by assigning to this parameter. Also (assuming
623 sufficient privileges), you may start a single command with a
624 different effective user ID by `(EUID=uid; command)'
625 If this is made local, it is not implicitly set to 0, but may be
627 explicitly set locally.
628 ERRNO <S>
630 The value of errno (see errno(3)) as set by the most recently
631 failed system call. This value is system dependent and is in‐
632 tended for debugging purposes. It is also useful with the
633 zsh/system module which allows the number to be turned into a
634 name or message.
635 FUNCNEST <S>
637 Integer. If greater than or equal to zero, the maximum nesting
638 depth of shell functions. When it is exceeded, an error is
639 raised at the point where a function is called. The default
640 value is determined when the shell is configured, but is typi‐
641 cally 500. Increasing the value increases the danger of a run‐
642 away function recursion causing the shell to crash. Setting a
643 negative value turns off the check.
644 GID <S>
646 The real group ID of the shell process. If you have sufficient
647 privileges, you may change the group ID of the shell process by
648 assigning to this parameter. Also (assuming sufficient privi‐
649 leges), you may start a single command under a different group
650 ID by `(GID=gid; command)'
651 If this is made local, it is not implicitly set to 0, but may be
653 explicitly set locally.
654 HISTCMD
656 The current history event number in an interactive shell, in
657 other words the event number for the command that caused
658 $HISTCMD to be read. If the current history event modifies the
659 history, HISTCMD changes to the new maximum history event num‐
660 ber.
661 HOST The current hostname.
663 LINENO <S>
665 The line number of the current line within the current script,
666 sourced file, or shell function being executed, whichever was
667 started most recently. Note that in the case of shell functions
668 the line number refers to the function as it appeared in the
669 original definition, not necessarily as displayed by the func‐
670 tions builtin.
671 LOGNAME
673 If the corresponding variable is not set in the environment of
674 the shell, it is initialized to the login name corresponding to
675 the current login session. This parameter is exported by default
676 but this can be disabled using the typeset builtin. The value
677 is set to the string returned by the getlogin(3) system call if
678 that is available.
679 MACHTYPE
681 The machine type (microprocessor class or machine model), as de‐
682 termined at compile time.
683 OLDPWD The previous working directory. This is set when the shell ini‐
685 tializes and whenever the directory changes.
686 OPTARG <S>
688 The value of the last option argument processed by the getopts
689 command.
690 OPTIND <S>
692 The index of the last option argument processed by the getopts
693 command.
694 OSTYPE The operating system, as determined at compile time.
696 PPID <S>
698 The process ID of the parent of the shell. As for $$, the value
699 indicates the parent of the original shell and does not change
700 in subshells.
701 PWD The present working directory. This is set when the shell ini‐
703 tializes and whenever the directory changes.
704 RANDOM <S>
706 A pseudo-random integer from 0 to 32767, newly generated each
707 time this parameter is referenced. The random number generator
708 can be seeded by assigning a numeric value to RANDOM.
709 The values of RANDOM form an intentionally-repeatable
711 pseudo-random sequence; subshells that reference RANDOM will re‐
712 sult in identical pseudo-random values unless the value of RAN‐
713 DOM is referenced or seeded in the parent shell in between sub‐
714 shell invocations.
715 SECONDS <S>
717 The number of seconds since shell invocation. If this parameter
718 is assigned a value, then the value returned upon reference will
719 be the value that was assigned plus the number of seconds since
720 the assignment.
721 Unlike other special parameters, the type of the SECONDS parame‐
723 ter can be changed using the typeset command. Only integer and
724 one of the floating point types are allowed. For example,
725 `typeset -F SECONDS' causes the value to be reported as a float‐
726 ing point number. The value is available to microsecond accu‐
727 racy, although the shell may show more or fewer digits depending
728 on the use of typeset. See the documentation for the builtin
729 typeset in zshbuiltins(1) for more details.
730 SHLVL <S>
732 Incremented by one each time a new shell is started.
733 signals
735 An array containing the names of the signals. Note that with
736 the standard zsh numbering of array indices, where the first el‐
737 ement has index 1, the signals are offset by 1 from the signal
738 number used by the operating system. For example, on typical
739 Unix-like systems HUP is signal number 1, but is referred to as
740 $signals[2]. This is because of EXIT at position 1 in the ar‐
741 ray, which is used internally by zsh but is not known to the op‐
742 erating system.
743 TRY_BLOCK_ERROR <S>
745 In an always block, indicates whether the preceding list of code
746 caused an error. The value is 1 to indicate an error, 0 other‐
747 wise. It may be reset, clearing the error condition. See Com‐
748 plex Commands in zshmisc(1)
749 TRY_BLOCK_INTERRUPT <S>
751 This variable works in a similar way to TRY_BLOCK_ERROR, but
752 represents the status of an interrupt from the signal SIGINT,
753 which typically comes from the keyboard when the user types ^C.
754 If set to 0, any such interrupt will be reset; otherwise, the
755 interrupt is propagated after the always block.
756 Note that it is possible that an interrupt arrives during the
758 execution of the always block; this interrupt is also propa‐
759 gated.
760 TTY The name of the tty associated with the shell, if any.
762 TTYIDLE <S>
764 The idle time of the tty associated with the shell in seconds or
765 -1 if there is no such tty.
766 UID <S>
768 The real user ID of the shell process. If you have sufficient
769 privileges, you may change the user ID of the shell by assigning
770 to this parameter. Also (assuming sufficient privileges), you
771 may start a single command under a different user ID by
772 `(UID=uid; command)'
773 If this is made local, it is not implicitly set to 0, but may be
775 explicitly set locally.
776 USERNAME <S>
778 The username corresponding to the real user ID of the shell
779 process. If you have sufficient privileges, you may change the
780 username (and also the user ID and group ID) of the shell by as‐
781 signing to this parameter. Also (assuming sufficient privi‐
782 leges), you may start a single command under a different user‐
783 name (and user ID and group ID) by `(USERNAME=username; com‐
784 mand)'
785 VENDOR The vendor, as determined at compile time.
787 zsh_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
789 An array (colon-separated list) indicating the context of shell
790 code that is being run. Each time a piece of shell code that is
791 stored within the shell is executed a string is temporarily ap‐
792 pended to the array to indicate the type of operation that is
793 being performed. Read in order the array gives an indication of
794 the stack of operations being performed with the most immediate
795 context last.
796 Note that the variable does not give information on syntactic
798 context such as pipelines or subshells. Use $ZSH_SUBSHELL to
799 detect subshells.
800 The context is one of the following:
802 cmdarg Code specified by the -c option to the command line that
803 invoked the shell.
804 cmdsubst
806 Command substitution using the `...` or $(...) construct.
807 equalsubst
809 File substitution using the =(...) construct.
810 eval Code executed by the eval builtin.
812 evalautofunc
814 Code executed with the KSH_AUTOLOAD mechanism in order to
815 define an autoloaded function.
816 fc Code from the shell history executed by the -e option to
818 the fc builtin.
819 file Lines of code being read directly from a file, for exam‐
821 ple by the source builtin.
822 filecode
824 Lines of code being read from a .zwc file instead of di‐
825 rectly from the source file.
826 globqual
828 Code executed by the e or + glob qualifier.
829 globsort
831 Code executed to order files by the o glob qualifier.
832 insubst
834 File substitution using the <(...) construct.
835 loadautofunc
837 Code read directly from a file to define an autoloaded
838 function.
839 outsubst
841 File substitution using the >(...) construct.
842 sched Code executed by the sched builtin.
844 shfunc A shell function.
846 stty Code passed to stty by the STTY environment variable.
848 Normally this is passed directly to the system's stty
849 command, so this value is unlikely to be seen in prac‐
850 tice.
851 style Code executed as part of a style retrieved by the zstyle
853 builtin from the zsh/zutil module.
854 toplevel
856 The highest execution level of a script or interactive
857 shell.
858 trap Code executed as a trap defined by the trap builtin.
860 Traps defined as functions have the context shfunc. As
861 traps are asynchronous they may have a different hierar‐
862 chy from other code.
863 zpty Code executed by the zpty builtin from the zsh/zpty mod‐
865 ule.
866 zregexparse-guard
868 Code executed as a guard by the zregexparse command from
869 the zsh/zutil module.
870 zregexparse-action
872 Code executed as an action by the zregexparse command
873 from the zsh/zutil module.
874 ZSH_ARGZERO
876 If zsh was invoked to run a script, this is the name of the
877 script. Otherwise, it is the name used to invoke the current
878 shell. This is the same as the value of $0 when the
879 POSIX_ARGZERO option is set, but is always available.
880 ZSH_EXECUTION_STRING
882 If the shell was started with the option -c, this contains the
883 argument passed to the option. Otherwise it is not set.
884 ZSH_NAME
886 Expands to the basename of the command used to invoke this in‐
887 stance of zsh.
888 ZSH_PATCHLEVEL
890 The output of `git describe --tags --long' for the zsh reposi‐
891 tory used to build the shell. This is most useful in order to
892 keep track of versions of the shell during development between
893 releases; hence most users should not use it and should instead
894 rely on $ZSH_VERSION.
895 zsh_scheduled_events
897 See the section `The zsh/sched Module' in zshmodules(1).
898 ZSH_SCRIPT
900 If zsh was invoked to run a script, this is the name of the
901 script, otherwise it is unset.
902 ZSH_SUBSHELL
904 Readonly integer. Initially zero, incremented each time the
905 shell forks to create a subshell for executing code. Hence
906 `(print $ZSH_SUBSHELL)' and `print $(print $ZSH_SUBSHELL)' out‐
907 put 1, while `( (print $ZSH_SUBSHELL) )' outputs 2.
908 ZSH_VERSION
910 The version number of the release of zsh.
911
913 The following parameters are used by the shell. Again, `<S>' indicates
914 that the parameter is special and `<Z>' indicates that the parameter
915 does not exist when the shell initializes in sh or ksh emulation mode.
916 In cases where there are two parameters with an upper- and lowercase
918 form of the same name, such as path and PATH, the lowercase form is an
919 array and the uppercase form is a scalar with the elements of the array
920 joined together by colons. These are similar to tied parameters cre‐
921 ated via `typeset -T'. The normal use for the colon-separated form is
922 for exporting to the environment, while the array form is easier to ma‐
923 nipulate within the shell. Note that unsetting either of the pair will
924 unset the other; they retain their special properties when recreated,
925 and recreating one of the pair will recreate the other.
926 ARGV0 If exported, its value is used as the argv[0] of external com‐
928 mands. Usually used in constructs like `ARGV0=emacs nethack'.
929 BAUD The rate in bits per second at which data reaches the terminal.
931 The line editor will use this value in order to compensate for a
932 slow terminal by delaying updates to the display until neces‐
933 sary. If the parameter is unset or the value is zero the com‐
934 pensation mechanism is turned off. The parameter is not set by
935 default.
936 This parameter may be profitably set in some circumstances, e.g.
938 for slow modems dialing into a communications server, or on a
939 slow wide area network. It should be set to the baud rate of
940 the slowest part of the link for best performance.
941 cdpath <S> <Z> (CDPATH <S>)
943 An array (colon-separated list) of directories specifying the
944 search path for the cd command.
945 COLUMNS <S>
947 The number of columns for this terminal session. Used for
948 printing select lists and for the line editor.
949 CORRECT_IGNORE
951 If set, is treated as a pattern during spelling correction. Any
952 potential correction that matches the pattern is ignored. For
953 example, if the value is `_*' then completion functions (which,
954 by convention, have names beginning with `_') will never be of‐
955 fered as spelling corrections. The pattern does not apply to
956 the correction of file names, as applied by the CORRECT_ALL op‐
957 tion (so with the example just given files beginning with `_' in
958 the current directory would still be completed).
959 CORRECT_IGNORE_FILE
961 If set, is treated as a pattern during spelling correction of
962 file names. Any file name that matches the pattern is never of‐
963 fered as a correction. For example, if the value is `.*' then
964 dot file names will never be offered as spelling corrections.
965 This is useful with the CORRECT_ALL option.
966 DIRSTACKSIZE
968 The maximum size of the directory stack, by default there is no
969 limit. If the stack gets larger than this, it will be truncated
970 automatically. This is useful with the AUTO_PUSHD option.
971 ENV If the ENV environment variable is set when zsh is invoked as sh
973 or ksh, $ENV is sourced after the profile scripts. The value of
974 ENV is subjected to parameter expansion, command substitution,
975 and arithmetic expansion before being interpreted as a pathname.
976 Note that ENV is not used unless the shell is interactive and
977 zsh is emulating sh or ksh.
978 FCEDIT The default editor for the fc builtin. If FCEDIT is not set,
980 the parameter EDITOR is used; if that is not set either, a
981 builtin default, usually vi, is used.
982 fignore <S> <Z> (FIGNORE <S>)
984 An array (colon separated list) containing the suffixes of files
985 to be ignored during filename completion. However, if comple‐
986 tion only generates files with suffixes in this list, then these
987 files are completed anyway.
988 fpath <S> <Z> (FPATH <S>)
990 An array (colon separated list) of directories specifying the
991 search path for function definitions. This path is searched
992 when a function with the -u attribute is referenced. If an exe‐
993 cutable file is found, then it is read and executed in the cur‐
994 rent environment.
995 histchars <S>
997 Three characters used by the shell's history and lexical analy‐
998 sis mechanism. The first character signals the start of a his‐
999 tory expansion (default `!'). The second character signals the
1000 start of a quick history substitution (default `^'). The third
1001 character is the comment character (default `#').
1002 The characters must be in the ASCII character set; any attempt
1004 to set histchars to characters with a locale-dependent meaning
1005 will be rejected with an error message.
1006 HISTCHARS <S> <Z>
1008 Same as histchars. (Deprecated.)
1009 HISTFILE
1011 The file to save the history in when an interactive shell exits.
1012 If unset, the history is not saved.
1013 HISTORY_IGNORE
1015 If set, is treated as a pattern at the time history files are
1016 written. Any potential history entry that matches the pattern
1017 is skipped. For example, if the value is `fc *' then commands
1018 that invoke the interactive history editor are never written to
1019 the history file.
1020 Note that HISTORY_IGNORE defines a single pattern: to specify
1022 alternatives use the `(first|second|...)' syntax.
1023 Compare the HIST_NO_STORE option or the zshaddhistory hook, ei‐
1025 ther of which would prevent such commands from being added to
1026 the interactive history at all. If you wish to use HISTORY_IG‐
1027 NORE to stop history being added in the first place, you can de‐
1028 fine the following hook:
1029 zshaddhistory() {
1031 emulate -L zsh
1032 ## uncomment if HISTORY_IGNORE
1033 ## should use EXTENDED_GLOB syntax
1034 # setopt extendedglob
1035 [[ $1 != ${~HISTORY_IGNORE} ]]
1036 }
1037 HISTSIZE <S>
1039 The maximum number of events stored in the internal history
1040 list. If you use the HIST_EXPIRE_DUPS_FIRST option, setting
1041 this value larger than the SAVEHIST size will give you the dif‐
1042 ference as a cushion for saving duplicated history events.
1043 If this is made local, it is not implicitly set to 0, but may be
1045 explicitly set locally.
1046 HOME <S>
1048 The default argument for the cd command. This is not set auto‐
1049 matically by the shell in sh, ksh or csh emulation, but it is
1050 typically present in the environment anyway, and if it becomes
1051 set it has its usual special behaviour.
1052 IFS <S>
1054 Internal field separators (by default space, tab, newline and
1055 NUL), that are used to separate words which result from command
1056 or parameter expansion and words read by the read builtin. Any
1057 characters from the set space, tab and newline that appear in
1058 the IFS are called IFS white space. One or more IFS white space
1059 characters or one non-IFS white space character together with
1060 any adjacent IFS white space character delimit a field. If an
1061 IFS white space character appears twice consecutively in the
1062 IFS, this character is treated as if it were not an IFS white
1063 space character.
1064 If the parameter is unset, the default is used. Note this has a
1066 different effect from setting the parameter to an empty string.
1067 KEYBOARD_HACK
1069 This variable defines a character to be removed from the end of
1070 the command line before interpreting it (interactive shells
1071 only). It is intended to fix the problem with keys placed annoy‐
1072 ingly close to return and replaces the SUNKEYBOARDHACK option
1073 which did this for backquotes only. Should the chosen character
1074 be one of singlequote, doublequote or backquote, there must also
1075 be an odd number of them on the command line for the last one to
1076 be removed.
1077 For backward compatibility, if the SUNKEYBOARDHACK option is ex‐
1079 plicitly set, the value of KEYBOARD_HACK reverts to backquote.
1080 If the option is explicitly unset, this variable is set to
1081 empty.
1082 KEYTIMEOUT
1084 The time the shell waits, in hundredths of seconds, for another
1085 key to be pressed when reading bound multi-character sequences.
1086 LANG <S>
1088 This variable determines the locale category for any category
1089 not specifically selected via a variable starting with `LC_'.
1090 LC_ALL <S>
1092 This variable overrides the value of the `LANG' variable and the
1093 value of any of the other variables starting with `LC_'.
1094 LC_COLLATE <S>
1096 This variable determines the locale category for character col‐
1097 lation information within ranges in glob brackets and for sort‐
1098 ing.
1099 LC_CTYPE <S>
1101 This variable determines the locale category for character han‐
1102 dling functions. If the MULTIBYTE option is in effect this
1103 variable or LANG should contain a value that reflects the char‐
1104 acter set in use, even if it is a single-byte character set, un‐
1105 less only the 7-bit subset (ASCII) is used. For example, if the
1106 character set is ISO-8859-1, a suitable value might be
1107 en_US.iso88591 (certain Linux distributions) or en_US.ISO8859-1
1108 (MacOS).
1109 LC_MESSAGES <S>
1111 This variable determines the language in which messages should
1112 be written. Note that zsh does not use message catalogs.
1113 LC_NUMERIC <S>
1115 This variable affects the decimal point character and thousands
1116 separator character for the formatted input/output functions and
1117 string conversion functions. Note that zsh ignores this setting
1118 when parsing floating point mathematical expressions.
1119 LC_TIME <S>
1121 This variable determines the locale category for date and time
1122 formatting in prompt escape sequences.
1123 LINES <S>
1125 The number of lines for this terminal session. Used for print‐
1126 ing select lists and for the line editor.
1127 LISTMAX
1129 In the line editor, the number of matches to list without asking
1130 first. If the value is negative, the list will be shown if it
1131 spans at most as many lines as given by the absolute value. If
1132 set to zero, the shell asks only if the top of the listing would
1133 scroll off the screen.
1134 LOGCHECK
1136 The interval in seconds between checks for login/logout activity
1137 using the watch parameter.
1138 MAIL If this parameter is set and mailpath is not set, the shell
1140 looks for mail in the specified file.
1141 MAILCHECK
1143 The interval in seconds between checks for new mail.
1144 mailpath <S> <Z> (MAILPATH <S>)
1146 An array (colon-separated list) of filenames to check for new
1147 mail. Each filename can be followed by a `?' and a message that
1148 will be printed. The message will undergo parameter expansion,
1149 command substitution and arithmetic expansion with the variable
1150 $_ defined as the name of the file that has changed. The de‐
1151 fault message is `You have new mail'. If an element is a direc‐
1152 tory instead of a file the shell will recursively check every
1153 file in every subdirectory of the element.
1154 manpath <S> <Z> (MANPATH <S> <Z>)
1156 An array (colon-separated list) whose value is not used by the
1157 shell. The manpath array can be useful, however, since setting
1158 it also sets MANPATH, and vice versa.
1159 match
1161 mbegin
1162 mend Arrays set by the shell when the b globbing flag is used in pat‐
1163 tern matches. See the subsection Globbing flags in the documen‐
1164 tation for Filename Generation in zshexpn(1).
1165 MATCH
1167 MBEGIN
1168 MEND Set by the shell when the m globbing flag is used in pattern
1169 matches. See the subsection Globbing flags in the documentation
1170 for Filename Generation in zshexpn(1).
1171 module_path <S> <Z> (MODULE_PATH <S>)
1173 An array (colon-separated list) of directories that zmodload
1174 searches for dynamically loadable modules. This is initialized
1175 to a standard pathname, usually `/usr/local/lib/zsh/$ZSH_VER‐
1176 SION'. (The `/usr/local/lib' part varies from installation to
1177 installation.) For security reasons, any value set in the envi‐
1178 ronment when the shell is started will be ignored.
1179 These parameters only exist if the installation supports dynamic
1181 module loading.
1182 NULLCMD <S>
1184 The command name to assume if a redirection is specified with no
1185 command. Defaults to cat. For sh/ksh behavior, change this to
1186 :. For csh-like behavior, unset this parameter; the shell will
1187 print an error message if null commands are entered.
1188 path <S> <Z> (PATH <S>)
1190 An array (colon-separated list) of directories to search for
1191 commands. When this parameter is set, each directory is scanned
1192 and all files found are put in a hash table.
1193 POSTEDIT <S>
1195 This string is output whenever the line editor exits. It usu‐
1196 ally contains termcap strings to reset the terminal.
1197 PROMPT <S> <Z>
1199 PROMPT2 <S> <Z>
1200 PROMPT3 <S> <Z>
1201 PROMPT4 <S> <Z>
1202 Same as PS1, PS2, PS3 and PS4, respectively.
1203 prompt <S> <Z>
1205 Same as PS1.
1206 PROMPT_EOL_MARK
1208 When the PROMPT_CR and PROMPT_SP options are set, the
1209 PROMPT_EOL_MARK parameter can be used to customize how the end
1210 of partial lines are shown. This parameter undergoes prompt ex‐
1211 pansion, with the PROMPT_PERCENT option set. If not set, the
1212 default behavior is equivalent to the value `%B%S%#%s%b'.
1213 PS1 <S>
1215 The primary prompt string, printed before a command is read. It
1216 undergoes a special form of expansion before being displayed;
1217 see EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The default is
1218 `%m%# '.
1219 PS2 <S>
1221 The secondary prompt, printed when the shell needs more informa‐
1222 tion to complete a command. It is expanded in the same way as
1223 PS1. The default is `%_> ', which displays any shell constructs
1224 or quotation marks which are currently being processed.
1225 PS3 <S>
1227 Selection prompt used within a select loop. It is expanded in
1228 the same way as PS1. The default is `?# '.
1229 PS4 <S>
1231 The execution trace prompt. Default is `+%N:%i> ', which dis‐
1232 plays the name of the current shell structure and the line num‐
1233 ber within it. In sh or ksh emulation, the default is `+ '.
1234 psvar <S> <Z> (PSVAR <S>)
1236 An array (colon-separated list) whose elements can be used in
1237 PROMPT strings. Setting psvar also sets PSVAR, and vice versa.
1238 READNULLCMD <S>
1240 The command name to assume if a single input redirection is
1241 specified with no command. Defaults to more.
1242 REPORTMEMORY
1244 If nonnegative, commands whose maximum resident set size
1245 (roughly speaking, main memory usage) in kilobytes is greater
1246 than this value have timing statistics reported. The format
1247 used to output statistics is the value of the TIMEFMT parameter,
1248 which is the same as for the REPORTTIME variable and the time
1249 builtin; note that by default this does not output memory usage.
1250 Appending " max RSS %M" to the value of TIMEFMT causes it to
1251 output the value that triggered the report. If REPORTTIME is
1252 also in use, at most a single report is printed for both trig‐
1253 gers. This feature requires the getrusage() system call, com‐
1254 monly supported by modern Unix-like systems.
1255 REPORTTIME
1257 If nonnegative, commands whose combined user and system execu‐
1258 tion times (measured in seconds) are greater than this value
1259 have timing statistics printed for them. Output is suppressed
1260 for commands executed within the line editor, including comple‐
1261 tion; commands explicitly marked with the time keyword still
1262 cause the summary to be printed in this case.
1263 REPLY This parameter is reserved by convention to pass string values
1265 between shell scripts and shell builtins in situations where a
1266 function call or redirection are impossible or undesirable. The
1267 read builtin and the select complex command may set REPLY, and
1268 filename generation both sets and examines its value when evalu‐
1269 ating certain expressions. Some modules also employ REPLY for
1270 similar purposes.
1271 reply As REPLY, but for array values rather than strings.
1273 RPROMPT <S>
1275 RPS1 <S>
1276 This prompt is displayed on the right-hand side of the screen
1277 when the primary prompt is being displayed on the left. This
1278 does not work if the SINGLE_LINE_ZLE option is set. It is ex‐
1279 panded in the same way as PS1.
1280 RPROMPT2 <S>
1282 RPS2 <S>
1283 This prompt is displayed on the right-hand side of the screen
1284 when the secondary prompt is being displayed on the left. This
1285 does not work if the SINGLE_LINE_ZLE option is set. It is ex‐
1286 panded in the same way as PS2.
1287 SAVEHIST
1289 The maximum number of history events to save in the history
1290 file.
1291 If this is made local, it is not implicitly set to 0, but may be
1293 explicitly set locally.
1294 SPROMPT <S>
1296 The prompt used for spelling correction. The sequence `%R' ex‐
1297 pands to the string which presumably needs spelling correction,
1298 and `%r' expands to the proposed correction. All other prompt
1299 escapes are also allowed.
1300 The actions available at the prompt are [nyae]:
1302 n (`no') (default)
1303 Discard the correction and run the command.
1304 y (`yes')
1305 Make the correction and run the command.
1306 a (`abort')
1307 Discard the entire command line without running it.
1308 e (`edit')
1309 Resume editing the command line.
1310 STTY If this parameter is set in a command's environment, the shell
1312 runs the stty command with the value of this parameter as argu‐
1313 ments in order to set up the terminal before executing the com‐
1314 mand. The modes apply only to the command, and are reset when it
1315 finishes or is suspended. If the command is suspended and con‐
1316 tinued later with the fg or wait builtins it will see the modes
1317 specified by STTY, as if it were not suspended. This (inten‐
1318 tionally) does not apply if the command is continued via `kill
1319 -CONT'. STTY is ignored if the command is run in the back‐
1320 ground, or if it is in the environment of the shell but not ex‐
1321 plicitly assigned to in the input line. This avoids running stty
1322 at every external command by accidentally exporting it. Also
1323 note that STTY should not be used for window size specifica‐
1324 tions; these will not be local to the command.
1325 TERM <S>
1327 The type of terminal in use. This is used when looking up term‐
1328 cap sequences. An assignment to TERM causes zsh to re-initial‐
1329 ize the terminal, even if the value does not change (e.g.,
1330 `TERM=$TERM'). It is necessary to make such an assignment upon
1331 any change to the terminal definition database or terminal type
1332 in order for the new settings to take effect.
1333 TERMINFO <S>
1335 A reference to your terminfo database, used by the `terminfo'
1336 library when the system has it; see terminfo(5). If set, this
1337 causes the shell to reinitialise the terminal, making the work‐
1338 around `TERM=$TERM' unnecessary.
1339 TERMINFO_DIRS <S>
1341 A colon-seprarated list of terminfo databases, used by the `ter‐
1342 minfo' library when the system has it; see terminfo(5). This
1343 variable is only used by certain terminal libraries, in particu‐
1344 lar ncurses; see terminfo(5) to check support on your system.
1345 If set, this causes the shell to reinitialise the terminal, mak‐
1346 ing the workaround `TERM=$TERM' unnecessary. Note that unlike
1347 other colon-separated arrays this is not tied to a zsh array.
1348 TIMEFMT
1350 The format of process time reports with the time keyword. The
1351 default is `%J %U user %S system %P cpu %*E total'. Recognizes
1352 the following escape sequences, although not all may be avail‐
1353 able on all systems, and some that are available may not be use‐
1354 ful:
1355 %% A `%'.
1357 %U CPU seconds spent in user mode.
1358 %S CPU seconds spent in kernel mode.
1359 %E Elapsed time in seconds.
1360 %P The CPU percentage, computed as 100*(%U+%S)/%E.
1361 %W Number of times the process was swapped.
1362 %X The average amount in (shared) text space used in kilo‐
1363 bytes.
1364 %D The average amount in (unshared) data/stack space used in
1365 kilobytes.
1366 %K The total space used (%X+%D) in kilobytes.
1367 %M The maximum memory the process had in use at any time in
1368 kilobytes.
1369 %F The number of major page faults (page needed to be
1370 brought from disk).
1371 %R The number of minor page faults.
1372 %I The number of input operations.
1373 %O The number of output operations.
1374 %r The number of socket messages received.
1375 %s The number of socket messages sent.
1376 %k The number of signals received.
1377 %w Number of voluntary context switches (waits).
1378 %c Number of involuntary context switches.
1379 %J The name of this job.
1380 A star may be inserted between the percent sign and flags print‐
1382 ing time (e.g., `%*E'); this causes the time to be printed in
1383 `hh:mm:ss.ttt' format (hours and minutes are only printed if
1384 they are not zero). Alternatively, `m' or `u' may be used
1385 (e.g., `%mE') to produce time output in milliseconds or mi‐
1386 croseconds, respectively.
1387 TMOUT If this parameter is nonzero, the shell will receive an ALRM
1389 signal if a command is not entered within the specified number
1390 of seconds after issuing a prompt. If there is a trap on
1391 SIGALRM, it will be executed and a new alarm is scheduled using
1392 the value of the TMOUT parameter after executing the trap. If
1393 no trap is set, and the idle time of the terminal is not less
1394 than the value of the TMOUT parameter, zsh terminates. Other‐
1395 wise a new alarm is scheduled to TMOUT seconds after the last
1396 keypress.
1397 TMPPREFIX
1399 A pathname prefix which the shell will use for all temporary
1400 files. Note that this should include an initial part for the
1401 file name as well as any directory names. The default is
1402 `/tmp/zsh'.
1403 TMPSUFFIX
1405 A filename suffix which the shell will use for temporary files
1406 created by process substitutions (e.g., `=(list)'). Note that
1407 the value should include a leading dot `.' if intended to be in‐
1408 terpreted as a file extension. The default is not to append any
1409 suffix, thus this parameter should be assigned only when needed
1410 and then unset again.
1411 watch <S> <Z> (WATCH <S>)
1413 An array (colon-separated list) of login/logout events to re‐
1414 port.
1415 If it contains the single word `all', then all login/logout
1417 events are reported. If it contains the single word `notme',
1418 then all events are reported as with `all' except $USERNAME.
1419 An entry in this list may consist of a username, an `@' followed
1421 by a remote hostname, and a `%' followed by a line (tty). Any
1422 of these may be a pattern (be sure to quote this during the as‐
1423 signment to watch so that it does not immediately perform file
1424 generation); the setting of the EXTENDED_GLOB option is re‐
1425 spected. Any or all of these components may be present in an
1426 entry; if a login/logout event matches all of them, it is re‐
1427 ported.
1428 For example, with the EXTENDED_GLOB option set, the following:
1430 watch=('^(pws|barts)')
1432 causes reports for activity associated with any user other than
1434 pws or barts.
1435 WATCHFMT
1437 The format of login/logout reports if the watch parameter is
1438 set. Default is `%n has %a %l from %m'. Recognizes the follow‐
1439 ing escape sequences:
1440 %n The name of the user that logged in/out.
1442 %a The observed action, i.e. "logged on" or "logged off".
1444 %l The line (tty) the user is logged in on.
1446 %M The full hostname of the remote host.
1448 %m The hostname up to the first `.'. If only the IP address
1450 is available or the utmp field contains the name of an
1451 X-windows display, the whole name is printed.
1452 NOTE: The `%m' and `%M' escapes will work only if there
1454 is a host name field in the utmp on your machine. Other‐
1455 wise they are treated as ordinary strings.
1456 %S (%s)
1458 Start (stop) standout mode.
1459 %U (%u)
1461 Start (stop) underline mode.
1462 %B (%b)
1464 Start (stop) boldface mode.
1465 %t
1467 %@ The time, in 12-hour, am/pm format.
1468 %T The time, in 24-hour format.
1470 %w The date in `day-dd' format.
1472 %W The date in `mm/dd/yy' format.
1474 %D The date in `yy-mm-dd' format.
1476 %D{string}
1478 The date formatted as string using the strftime function,
1479 with zsh extensions as described by EXPANSION OF PROMPT
1480 SEQUENCES in zshmisc(1).
1481 %(x:true-text:false-text)
1483 Specifies a ternary expression. The character following
1484 the x is arbitrary; the same character is used to sepa‐
1485 rate the text for the "true" result from that for the
1486 "false" result. Both the separator and the right paren‐
1487 thesis may be escaped with a backslash. Ternary expres‐
1488 sions may be nested.
1489 The test character x may be any one of `l', `n', `m' or
1491 `M', which indicate a `true' result if the corresponding
1492 escape sequence would return a non-empty value; or it may
1493 be `a', which indicates a `true' result if the watched
1494 user has logged in, or `false' if he has logged out.
1495 Other characters evaluate to neither true nor false; the
1496 entire expression is omitted in this case.
1497 If the result is `true', then the true-text is formatted
1499 according to the rules above and printed, and the
1500 false-text is skipped. If `false', the true-text is
1501 skipped and the false-text is formatted and printed. Ei‐
1502 ther or both of the branches may be empty, but both sepa‐
1503 rators must be present in any case.
1504 WORDCHARS <S>
1506 A list of non-alphanumeric characters considered part of a word
1507 by the line editor.
1508 ZBEEP If set, this gives a string of characters, which can use all the
1510 same codes as the bindkey command as described in the zsh/zle
1511 module entry in zshmodules(1), that will be output to the termi‐
1512 nal instead of beeping. This may have a visible instead of an
1513 audible effect; for example, the string `\e[?5h\e[?5l' on a
1514 vt100 or xterm will have the effect of flashing reverse video on
1515 and off (if you usually use reverse video, you should use the
1516 string `\e[?5l\e[?5h' instead). This takes precedence over the
1517 NOBEEP option.
1518 ZDOTDIR
1520 The directory to search for shell startup files (.zshrc, etc),
1521 if not $HOME.
1522 zle_bracketed_paste
1524 Many terminal emulators have a feature that allows applications
1525 to identify when text is pasted into the terminal rather than
1526 being typed normally. For ZLE, this means that special charac‐
1527 ters such as tabs and newlines can be inserted instead of invok‐
1528 ing editor commands. Furthermore, pasted text forms a single
1529 undo event and if the region is active, pasted text will replace
1530 the region.
1531 This two-element array contains the terminal escape sequences
1533 for enabling and disabling the feature. These escape sequences
1534 are used to enable bracketed paste when ZLE is active and dis‐
1535 able it at other times. Unsetting the parameter has the effect
1536 of ensuring that bracketed paste remains disabled.
1537 zle_highlight
1539 An array describing contexts in which ZLE should highlight the
1540 input text. See Character Highlighting in zshzle(1).
1541 ZLE_LINE_ABORTED
1543 This parameter is set by the line editor when an error occurs.
1544 It contains the line that was being edited at the point of the
1545 error. `print -zr -- $ZLE_LINE_ABORTED' can be used to recover
1546 the line. Only the most recent line of this kind is remembered.
1547 ZLE_REMOVE_SUFFIX_CHARS
1549 ZLE_SPACE_SUFFIX_CHARS
1550 These parameters are used by the line editor. In certain cir‐
1551 cumstances suffixes (typically space or slash) added by the com‐
1552 pletion system will be removed automatically, either because the
1553 next editing command was not an insertable character, or because
1554 the character was marked as requiring the suffix to be removed.
1555 These variables can contain the sets of characters that will
1557 cause the suffix to be removed. If ZLE_REMOVE_SUFFIX_CHARS is
1558 set, those characters will cause the suffix to be removed; if
1559 ZLE_SPACE_SUFFIX_CHARS is set, those characters will cause the
1560 suffix to be removed and replaced by a space.
1561 If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is
1563 equivalent to:
1564 ZLE_REMOVE_SUFFIX_CHARS=$' \t\n;&|'
1566 If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no characters
1568 have this behaviour. ZLE_SPACE_SUFFIX_CHARS takes precedence,
1569 so that the following:
1570 ZLE_SPACE_SUFFIX_CHARS=$'&|'
1572 causes the characters `&' and `|' to remove the suffix but to
1574 replace it with a space.
1575 To illustrate the difference, suppose that the option AUTO_RE‐
1577 MOVE_SLASH is in effect and the directory DIR has just been com‐
1578 pleted, with an appended /, following which the user types `&'.
1579 The default result is `DIR&'. With ZLE_REMOVE_SUFFIX_CHARS set
1580 but without including `&' the result is `DIR/&'. With
1581 ZLE_SPACE_SUFFIX_CHARS set to include `&' the result is `DIR &'.
1582 Note that certain completions may provide their own suffix re‐
1584 moval or replacement behaviour which overrides the values de‐
1585 scribed here. See the completion system documentation in zsh‐
1586 compsys(1).
1587 ZLE_RPROMPT_INDENT <S>
1589 If set, used to give the indentation between the right hand side
1590 of the right prompt in the line editor as given by RPS1 or
1591 RPROMPT and the right hand side of the screen. If not set, the
1592 value 1 is used.
1593 Typically this will be used to set the value to 0 so that the
1595 prompt appears flush with the right hand side of the screen.
1596 This is not the default as many terminals do not handle this
1597 correctly, in particular when the prompt appears at the extreme
1598 bottom right of the screen. Recent virtual terminals are more
1599 likely to handle this case correctly. Some experimentation is
1600 necessary.
1601zsh 5.8.1 February 12, 2022 ZSHPARAM(1)