set(1) manual page
Table of Contents
set, unset, setenv, unsetenv, export - shell built-in functions to
determine the characteristics for environmental variables of the current
shell and its descendents
set [ --aefhkntuvx [ argument ... ] ]
unset
[ name ... ]
export [ name ... ]
set [var [ = value ] ]
- set var[n] = word
unset pattern
setenv [
VAR [ word ] ]
unsetenv variable
set [ ±aefhkmnopstuvx
] [ ±o option ]... [ ±A name ] [ arg ... ]
unset [ -f ] name ...
**
- export [ name[=value] ] ...
-
SUNWcsu
The
set built-in command has the following options:
- -a
- Mark variables which are
modified or created for export.
- -e
- Exit immediately if a command exits with
a non-zero exit status.
- -f
- Disable file name generation.
- -h
- Locate and remember
function commands as functions are defined (function commands are normally
located when the function is executed).
- -k
- All keyword arguments are placed
in the environment for a command, not just those that precede the command
name.
- -n
- Read commands but do not execute them.
- -t
- Exit after reading and executing
one command.
- -u
- Treat unset variables as an error when substituting.
- -v
- Print
shell input lines as they are read.
- -x
- Print commands and their arguments
as they are executed.
- --
- Do not change any of the flags; useful in setting
$1 to -.
Using + rather than - causes these flags to be turned off. These flags
can also be used upon invocation of the shell. The current set of flags
may be found in $-.
The remaining arguments are positional parameters and are assigned, in
order, to $1, $2, .... If no arguments are given the values of all names are
printed.
For each name, unset removes the corresponding variable or function
value. The variables PATH
, PS1
, PS2
, MAILCHECK
, and IF
cannot be unset.
With the export built-in, the given names are marked for automatic export
to the environment of subsequently executed commands. If no arguments are
given, variable names that have been marked for export during the current
shell’s execution are listed. (Variable names exported from a parent shell
are listed only if they have been exported again during the current shell’s
execution.) Function names are not exported.
With no arguments, set displays
the values of all shell variables. Multiword values are displayed as a parenthesized
list. With the var argument alone, set assigns an empty (null) value to
the variable var. With arguments of the form var = value set assigns value
to var, where value is one of:
- word
- A single word (or quoted string).
- (wordlist)
- A space-separated list of words enclosed in parentheses.
Values
are command and filename expanded before being assigned. The form set var[n]
= word replaces the n’th word in a multiword value with word.
unset removes
variables whose names match (filename substitution) pattern. All variables
are removed by ‘unset *’; this has noticeably distasteful side effects.
With
no arguments, setenv displays all environment variables. With the
VAR argument,
setenv sets the environment variable
VAR to an empty (null) value. (By
convention, environment variables are normally given upper-case names.) With
both
VAR and word arguments specified, setenv sets
VAR to word, which
must be either a single word or a quoted string. The PATH
variable can
take multiple word arguments, separated by colons (see EXAMPLES). The
most commonly used environment variables, USER
, TERM
, and PATH
, are automatically
imported to and exported from the csh variables user, term, and path. Use
setenv if you need to change these variables. In addition, the shell sets
the PWD
environment variable from the csh variable cwd whenever the latter
changes.
The environment variables LC_CTYPE, LC_MESSAGES, LC_TIME, LC_COLLATE,
LC_NUMERIC,
and LC_MONETARY
take immediate effect when changed within
the C shell. See environ(5)
for descriptions of these environment variables.
unsetenv removes variable from the environment. As with unset, pattern matching
is not performed.
The flags for the set built-in have meaning as follows:
- -A
- Array assignment. Unset the variable name and assign values sequentially
from the list arg. If +A is used, the variable name is not unset first.
- -a
- All subsequent variables that are defined are automatically exported.
- -e
- If a command has a non-zero exit status, execute the ERR
trap, if set,
and exit. This mode is disabled while reading profiles.
- -f
- Disables file
name generation.
- -h
- Each command becomes a tracked alias when first encountered.
- -k
- All variable assignment arguments are placed in the environment for a
command, not just those that precede the command name.
- -m
- Background jobs
will run in a separate process group and a line will print upon completion.
The exit status of background jobs is reported in a completion message.
On systems with job control, this flag is turned on automatically for
interactive shells.
- -n
- Read commands and check them for syntax errors, but
do not execute them. Ignored for interactive shells.
- -o
- The following argument
can be one of the following option names:
- allexport
- Same as -a.
- errexit
- Same
as -e.
- bgnice
- All background jobs are run at a lower priority. This is the
default mode. emacs Puts you in an emacs style in-line editor for command
entry.
- gmacs
- Puts you in a gmacs style in-line editor for command entry.
- ignoreeof
- The shell will not exit on end-of-file. The command exit must be used.
- keyword
- Same as -k.
- markdirs
- All directory names resulting from file name generation
have a trailing / appended.
- monitor
- Same as -m.
- noclobber
- Prevents redirection
> from truncating existing files. Require >| to truncate a file when turned
on.
- noexec
- Same as -n.
- noglob
- Same as -f.
- nolog
- Do not save function definitions
in history file.
- nounset
- Same as -u.
- privileged
- Same as -p.
- verbose
- Same as
-v.
- trackall
- Same as -h.
- vi
- Puts you in insert mode of a vi style in-line editor
until you hit escape character 033. This puts you in control mode. A return
sends the line.
- viraw
- Each character is processed as it is typed in vi mode.
- xtrace
- Same as -x.
If no option name is supplied then the current option
settings are printed.
- -p
- Disables processing of the $HOME
/.profile file and
uses the file /etc/suid_profile instead of the ENV
file. This mode is
on whenever the effective uid is not equal to the real uid, or when the
effective gid is not equal to the real gid. Turning this off causes the
effective uid and gid to be set to the real uid and gid.
- -s
- Sort the positional
parameters lexicographically.
- -t
- Exit after reading and executing one command.
- -u
- Treat unset parameters as an error when substituting.
- -v
- Print shell input
lines as they are read.
- -x
- Print commands and their arguments as they are
executed.
- -
- Turns off -x and -v flags and stops examining arguments for flags.
- --
- Do not change any of the flags; useful in setting $1 to a value beginning
with -. If no arguments follow this flag then the positional parameters are
unset.
Using + rather than - causes these flags to be turned off. These flags
can also be used upon invocation of the shell. The current set of flags
may be found in $-. Unless -A is specified, the remaining arguments are positional
parameters and are assigned, in order, to $1 $2 .... If no arguments are given
then the names and values of all variables are printed on the standard
output.
The variables given by the list of names are unassigned, i.e., their
values and attributes are erased. readonly variables cannot be unset. If
the -f, flag is set, then the names refer to function names. Unsetting
ERRNO,
LINENO,
MAILCHECK,
OPTARG,
OPTIND,
RANDOM,
SECONDS,
TMOUT, and
_ removes their special meaning even if they are subsequently
assigned.
When using unset, the variables given by the list of names are
unassigned, i.e., their values and attributes are erased. readonly variables
cannot be unset. If the -f, flag is set, then the names refer to function
names. Unsetting
ERRNO,
LINENO,
MAILCHECK,
OPTARG,
OPTIND,
RANDOM,
SECONDS,
TMOUT, and
_ removes their special meaning even if they are
subsequently assigned.
With the export built-in, the given names are marked
for automatic export to the environment of subsequently-executed commands.
On this man page, ksh(1)
commands that are preceded by one or two * (asterisks)
are treated specially in the following ways:
.- Variable assignment lists
preceding the command remain in effect when the command completes.
.- I/O redirections
are processed after variable assignments.
.- Errors cause a script that contains
them to abort.
.- Words, following a command preceded by ** that are in the
format of a variable assignment, are expanded with the same rules as a
variable assignment. This means that tilde substitution is performed after
the = sign and word splitting and file name generation are not performed.
The following example sets the PATH
variable to search for
files in the /bin, /usr/bin, /usr/sbin, and /usr/ucb/bin directories,
in that order.
setenv PATH "/bin:/usr/bin:/usr/sbin:usr/ucb/bin"
csh(1)
,
ksh(1)
, read(1)
, sh(1)
, typeset(1)
, environ(5)
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