1set(1) User Commands set(1)
2
6 set, unset, setenv, unsetenv, export - shell built-in functions to
7 determine the characteristics for environmental variables of the cur‐
8 rent shell and its descendents
9
11 sh
12 set [--aefhkntuvx [argument]]...
13 unset [name]...
16 export [name]...
19 csh
22 set [var [= value]]
23 set var [n] = word
26 unset pattern
29 setenv [VAR [word]]
32 unsetenv variable
35 ksh
38 set [±abCefhkmnopstuvx] [±o option]... [±A name]
39 [arg]...
40 unset [-f] name...
43 **export [name [=value]]...
46 **export [-p]
49 ksh93
52 +set [±abCefGhkmnoprstuvx] [±o option]... [±A vname]
53 [arg]...
54 +unset [-fnv] vname...
57 ++export [-p] [name[=value]]...
60
63 sh
64 The set built-in command has the following options:
65 -- Does not change any of the flags. This option is useful in set‐
67 ting $1 to −.
68 -a Marks variables which are modified or created for export.
71 -e Exits immediately if a command exits with a non-zero exit status.
74 -f Disables file name generation.
77 -h Locates and remembers function commands as functions are defined.
80 Function commands are normally located when the function is exe‐
81 cuted.
82 -k All keyword arguments are placed in the environment for a com‐
85 mand, not just those that precede the command name.
86 -n Reads commands but does not execute them.
89 -t Exits after reading and executing one command.
92 -u Treats unset variables as an error when substituting.
95 -v Prints shell input lines as they are read.
98 -x Prints commands and their arguments as they are executed.
101 Using + rather than − causes these flags to be turned off. These flags
105 can also be used upon invocation of the shell. The current set of flags
106 can be found in $−. The remaining arguments are positional parameters
107 and are assigned, in order, to $1, $2, .... If no arguments are speci‐
108 fied the values of all names are printed.
109 For each name, unset removes the corresponding variable or function
112 value. The variables PATH, PS1, PS2, MAILCHECK, and IF cannot be unset.
113 With the export built-in, the specified names are marked for automatic
116 export to the environment of subsequently executed commands. If no
117 arguments are specified, variable names that have been marked for
118 export during the current shell's execution are listed. Function names
119 are not exported.
120 csh
122 With no arguments, set displays the values of all shell variables. Mul‐
123 tiword values are displayed as a parenthesized list. With the var argu‐
124 ment alone, set assigns an empty (null) value to the variable var. With
125 arguments of the form var = value set assigns value to var, where value
126 is one of:
127 word A single word (or quoted string).
129 (wordlist) A space-separated list of words enclosed in parentheses.
132 Values are command and filename expanded before being assigned. The
136 form set var[n]=word replaces the n'th word in a multiword value with
137 word.
138 unset removes variables whose names match (filename substitution) pat‐
141 tern. All variables are removed by `unset *'.
142 With no arguments, setenv displays all environment variables. With the
145 VAR argument, setenv sets the environment variable VAR to an empty
146 (null) value. (By convention, environment variables are normally speci‐
147 fied upper-case names.) With both VAR and word arguments specified,
148 setenv sets VAR to word, which must be either a single word or a quoted
149 string. The PATH variable can take multiple word arguments, separated
150 by colons (see EXAMPLES). The most commonly used environment variables,
151 USER, TERM, and PATH, are automatically imported to and exported from
152 the csh variables user, term, and path. Use setenv if you need to
153 change these variables. In addition, the shell sets the PWD environment
154 variable from the csh variable cwd whenever the latter changes.
155 The environment variables LC_CTYPE, LC_MESSAGES, LC_TIME, LC_COLLATE,
158 LC_NUMERIC, and LC_MONETARY take immediate effect when changed within
159 the C shell. See environ(5) for descriptions of these environment vari‐
160 ables.
161 unsetenv removes variable from the environment. As with unset, pattern
164 matching is not performed.
165 ksh
167 The flags for the set built-in have meaning as follows:
168 -A Array assignment. Unsets the variable name and assigns
170 values sequentially from the list arg. If +A is used, the
171 variable name is not unset first.
172 -a All subsequent variables that are defined are automati‐
175 cally exported.
176 -b Causes the shell to notify the user asynchronously of
179 background job completions.
180 -C Prevents existing files from being overwritten by the
183 shell's > redirection operator. The >| redirection opera‐
184 tor overrides this noclobber option for an individual
185 file.
186 -e If a command has a non-zero exit status, executes the ERR
189 trap, if set, and exits. This mode is disabled while read‐
190 ing profiles.
191 -f Disables file name generation.
194 -h Each command becomes a tracked alias when first encoun‐
197 tered.
198 -k All variable assignment arguments are placed in the envi‐
201 ronment for a command, not just those that precede the
202 command name.
203 -m Background jobs run in a separate process group and a line
206 prints upon completion. The exit status of background jobs
207 is reported in a completion message. On systems with job
208 control, this flag is turned on automatically for interac‐
209 tive shells.
210 -n Reads commands and checks them for syntax errors, but does
213 not execute them. Ignored for interactive shells.
214 +o Writes the current option stettings to standard output in
217 a format that is suitable for reinput to the shell as com‐
218 mands that achieve the same option settings.
219 -o option The option argument can be one of the following option
222 names:
223 allexport Same as -a.
225 errexit Same as -e.
228 bgnice All background jobs are run at a lower pri‐
231 ority. This is the default mode. emacs Puts
232 you in an emacs style in-line editor for
233 command entry.
234 gmacs Puts you in a gmacs style in-line editor for
237 command entry.
238 ignoreeof The shell does not exit on end-of-file. The
241 command exit must be used.
242 keyword Same as -k.
245 markdirs All directory names resulting from file name
248 generation have a trailing / appended.
249 monitor Same as -m.
252 noclobber Prevents redirection operator > from trun‐
255 cating existing files. Requires the >| oper‐
256 ator to truncate a file when turned on. Same
257 as -C.
258 noexec Same as -n.
261 noglob Same as -f.
264 nolog Does not save function definitions in his‐
267 tory file.
268 notify Same as -b.
271 nounset Same as -u.
274 privileged Same as -p.
277 verbose Same as -v.
280 trackall Same as -h.
283 vi Puts you in insert mode of a vi style in-
286 line editor until you hit escape character
287 033. This puts you in control mode. A return
288 sends the line.
289 viraw Each character is processed as it is typed
292 in vi mode.
293 xtrace Same as -x.
296 If no option name is supplied then the current option settings are
301 printed.
302 -p Disables processing of the $HOME/.profile file and uses the
304 file /etc/suid_profile instead of the ENV file. This mode is on
305 whenever the effective uid is not equal to the real uid, or
306 when the effective gid is not equal to the real gid. Turning
307 this off causes the effective uid and gid to be set to the real
308 uid and gid.
309 -s Sorts the positional parameters lexicographically.
312 -t Exits after reading and executing one command.
315 -u Treats unset parameters as an error when substituting.
318 -v Prints shell input lines as they are read.
321 -x Prints commands and their arguments as they are executed.
324 − Turns off -x and -v flags and stops examining arguments for
327 flags.
328 - Does not change any of the flags. This option is useful in set‐
331 ting $1 to a value beginning with −. If no arguments follow
332 this flag then the positional parameters are unset.
333 Using + rather than − causes these flags to be turned off. These flags
337 can also be used upon invocation of the shell. The current set of flags
338 can be found in $−. Unless -A is specified, the remaining arguments are
339 positional parameters and are assigned, in order, to $1 $2 .... If no
340 arguments are specified then the names and values of all variables are
341 printed on the standard output.
342 The variables specified by the list of names are unassigned, that is,
345 their values and attributes are erased. readonly variables cannot be
346 unset. If the -f flag is set, then the names refer to function names.
347 Unsetting ERRNO, LINENO, MAILCHECK, OPTARG, OPTIND, RANDOM, SECONDS,
348 TMOUT, and _ removes their special meaning even if they are subse‐
349 quently assigned.
350 When using unset, the variables specified by the list of names are
353 unassigned, i.e., their values and attributes are erased. readonly
354 variables cannot be unset. If the -f, flag is set, then the names refer
355 to function names. Unsetting ERRNO, LINENO, MAILCHECK, OPTARG, OPTIND,
356 RANDOM, SECONDS, TMOUT, and _ removes their special meaning even if
357 they are subsequently assigned.
358 With the export built-in, the specified names are marked for automatic
361 export to the environment of subsequently-executed commands.
362 When -p is specified, export writes to the standard output the names
365 and values of all exported variables in the following format:
366 "export %s=%s\n", name, value
368 if name is set, and:
373 "export %s\n", name
375 if name is unset.
380 The shell formats the output, including the proper use of quoting, so
383 that it is suitable for reinput to the shell as commands that achieve
384 the same exporting results, except for the following:
385 1. Read-only variables with values cannot be reset.
387 2. Variables that were unset at the time they were output are
389 not reset to the unset state if a value is assigned to the
390 variable between the time the state was saved and the time
391 at which the saved output is reinput to the shell.
392 On this manual page, ksh(1) commands that are preceded by one or two *
395 (asterisks) are treated specially in the following ways:
396 1. Variable assignment lists preceding the command remain in
398 effect when the command completes.
399 2. I/O redirections are processed after variable assignments.
401 3. Errors cause a script that contains them to abort.
403 4. Words, following a command preceded by ** that are in the
405 format of a variable assignment, are expanded with the same
406 rules as a variable assignment. This means that tilde sub‐
407 stitution is performed after the = sign and word splitting
408 and file name generation are not performed.
409 ksh93
411 set sets or unsets options and positional parameters. Options that are
412 specified with a - cause the options to be set. Options that are speci‐
413 fied with a + cause the option to be unset.
414 set without any options or arguments displays the names and values of
417 all shell variables in the order of the collation sequence in the cur‐
418 rent locale. The values are quoted so that they are suitable for input
419 again to the shell.
420 If no arguments are specified, not even the end of options argument --,
423 the positional parameters are unchanged. Otherwise, unless the -A
424 option has been specified, the positional parameters are replaced by
425 the list of arguments. A first argument of -- is ignored when setting
426 positional parameters.
427 For backwards compatibility, a set command without any options speci‐
430 fied, whose first argument is - turns off the -v and -x options. If any
431 additional arguments are specified, they replace the positional parame‐
432 ters.
433 The options for set in ksh93 are:
436 -a Set the export attribute for each variable whose name
438 does not contain a . that you assign a value in the cur‐
439 rent shell environment.
440 -A name Assign the arguments sequentially to the array named by
443 name starting at subscript 0 rather than to the posi‐
444 tional parameters.
445 -b The shell writes a message to standard error as soon it
448 detects that a background job completes rather than
449 waiting until the next prompt.
450 -B Enable {...} group expansion. On by default.
453 -C Prevents existing regular files from being overwritten
456 using the > redirection operator. The >| redirection
457 overrides this noclobber option.
458 -e A simple command that has a non-zero exit status causes
461 the shell to exit unless the simple command is:
462 o contained in an && or || list
464 o the command immediately following if, while,
466 or until
467 o contained in the pipeline following !
469 -f Pathname expansion is disabled.
472 -G Causes ** by itself to also match all sub-directories
475 during pathname expansion.
476 -h Obsolete. Causes each command whose name has the syntax
479 of an alias to become a tracked alias when it is first
480 encountered.
481 -H Enable !-style history expansion similar to csh.
484 -k This is obsolete. All arguments of the form name=value
487 are removed and placed in the variable assignment list
488 for the command. Ordinarily, variable assignments must
489 precede command arguments.
490 -m When enabled, the shell runs background jobs in a sepa‐
493 rate process group and displays a line upon completion.
494 This mode is enabled by default for interactive shells
495 on systems that support job control.
496 -n The shell reads commands and checks for syntax errors,
499 but does not execute the command. Usually specified on
500 command invocation.
501 -o [option] If option is not specified, the list of options and
504 their current settings is written to standard output.
505 When invoked with a + the options are written in a for‐
506 mat that can be input again to the shell to restore the
507 settings. This option can be repeated to enable or dis‐
508 able multiple options.
509 The value of option must be one of the following:
511 allexport Same as -a.
513 bgnice All background jobs are run at lower pri‐
516 orities.
517 braceexpand Same as -B.
520 emacs Enables or disables emacs editing mode.
523 errexit Same as -e.
526 globstar Equivalent to -G.
529 gmacs Enables or disables gmacs. gmacs editing
532 mode is the same as emacs editing mode,
533 except for the handling of CTRL-T.
534 histexpand Same as -H.
537 ignoreeof The interactive shell does not exit on
540 end-of-file.
541 keyword Same as -k.
544 markdirs All directory names resulting from file
547 name generation have a trailing /
548 appended.
549 monitor Same as -m.
552 multiline Use multiple lines when editing lines
555 that are longer than the window width.
556 noclobber Same as -C.
559 noexec Same as -n.
562 noglob Same as -f.
565 nolog This has no effect. It is provided for
568 backward compatibility.
569 notify Same as -b.
572 nounset Same as -u.
575 pipefail A pipeline does not complete until all
578 components of the pipeline have com‐
579 pleted, and the exit status of the pipe‐
580 line is the value of the last command to
581 exit with non-zero exit status, or is
582 zero if all commands return zero exit
583 status.
584 privileged Same as -p.
587 showme Simple commands preceded by a ; are
590 traced as if -x were enabled but not exe‐
591 cuted.
592 trackall Same as -h.
595 verbose Same as -v.
598 vi Enables or disables vi editing mode.
601 viraw Does not use canonical input mode when
604 using vi edit mode
605 xtrace Same as -x.
608 -p Privileged mode. Disabling -p sets the effective user id
612 to the real user id, and the effective group id to the
613 real group id. Enabling -p restores the effective user
614 and group ids to their values when the shell was
615 invoked. The -p option is on whenever the real and
616 effective user id is not equal or the real and effective
617 group id is not equal. User profiles are not processed
618 when -p is enabled.
619 -r Restricted. Enables restricted shell. This option cannot
622 be unset once enabled.
623 -s Sort the positional parameters
626 -t Obsolete. The shell reads one command and then exits.
629 -u If enabled, the shell displays an error message when it
632 tries to expand a variable that is unset.
633 -v Verbose. The shell displays its input onto standard
636 error as it reads it.
637 -x Execution trace. The shell displays each command after
640 all expansion and before execution preceded by the
641 expanded value of the PS4 parameter.
642 The following exit values are returned by set in ksh93:
646 0 Successful completion.
648 >0 An error occurred.
651 For each name specified, unset unsets the variable, or function if -f
655 is specified, from the current shell execution environment. Read-only
656 variables cannot be unset.
657 The options for unset in ksh93 are:
660 -f Where name refers to a function name, the shell unsets the func‐
662 tion definition.
663 -n If name refers to variable that is a reference, the variable name
666 is unset rather than the variable it references. Otherwise, this
667 option is equivalent to the -v option.
668 -v Where name refers to a variable name, the shell unsets it and
671 removes it from the environment. This is the default behavior.
672 The following exit values are returned by unset in ksh93:
676 0 Successful completion. All names were successfully unset.
678 >0 An error occurred, or one or more name operands could not be
681 unset
682 export sets the export attribute on each of the variables specified by
686 name which causes them to be in the environment of subsequently exe‐
687 cuted commands. If =value is specified, the variable name is set to
688 value.
689 If no name is specified, the names and values of all exported variables
692 are written to standard output.
693 export is built-in to the shell as a declaration command so that field
696 splitting and pathname expansion are not performed on the arguments.
697 Tilde expansion occurs on value.
698 The options for export in ksh93 are:
701 -p Causes the output to be in the form of export commands that can
703 be used as input to the shell to recreate the current exports.
704 The following exit values are returned by export in ksh93:
708 0 Successful completion.
710 >0 An error occurred.
713 On this manual page, ksh93(1) commands that are preceded by one or two
717 + are treated specially in the following ways:
718 1. Variable assignment lists preceding the command remain in
720 effect when the command completes.
721 2. I/O redirections are processed after variable assignments.
723 3. Errors cause a script that contains them to abort.
725 4. They are not valid function names.
727 5. Words, following a command preceded by ++ that are in the
729 format of a variable assignment, are expanded with the same
730 rules as a variable assignment. This means that tilde sub‐
731 stitution is performed after the = sign and field splitting
732 and file name generation are not performed.
733
735 csh
736 The following example sets the PATH variable to search for files in the
737 /bin, /usr/bin, /usr/sbin, and /usr/ucb/bin directories, in that order:
738 setenv PATH "/bin:/usr/bin:/usr/sbin:usr/ucb/bin"
740
744 See attributes(5) for descriptions of the following attributes:
745 ┌─────────────────────────────┬─────────────────────────────┐
750 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
751 ├─────────────────────────────┼─────────────────────────────┤
752 │Availability │SUNWcsu │
753 └─────────────────────────────┴─────────────────────────────┘
754
756 csh(1), ksh(1), ksh93(1), read(1), sh(1), typeset(1), attributes(5),
757 environ(5)
758SunOS 5.11 20 Nov 2007 set(1)