set(1)								   User Commands							    set(1)

NAME

       set, unset, setenv, unsetenv, export - shell built-in functions to determine the characteristics for environmental variables of the current
       shell and its descendents

SYNOPSIS

   sh
       set [--aefhkntuvx [argument]]...

       unset [name]...

       export [name]...

   csh
       set [var [= value]]

       set var [n] = word

       unset pattern

       setenv [VAR [word]]

       unsetenv variable

   ksh
       set [+-abCefhkmnopstuvx] [+-o option]... [+-A name]
	    [arg]...

       unset [-f] name...

       **export [name [=value]]...

       **export [-p]

   ksh93
       +set [+-abCefGhkmnoprstuvx] [+-o option]... [+-A vname]
	    [arg]...

       +unset [-fnv] vname...

       ++export [-p] [name[=value]]...

DESCRIPTION

   sh
       The set built-in command has the following options:

       --    Does not change any of the flags. This option is useful in setting $1 to -.

       -a    Marks variables which are modified or created for export.

       -e    Exits immediately if a command exits with a non-zero exit status.

       -f    Disables file name generation.

       -h    Locates and remembers function commands as functions are defined. Function commands are normally located when the	function  is  exe-
	     cuted.

       -k    All keyword arguments are placed in the environment for a command, not just those that precede the command name.

       -n    Reads commands but does not execute them.

       -t    Exits after reading and executing one command.

       -u    Treats unset variables as an error when substituting.

       -v    Prints shell input lines as they are read.

       -x    Prints commands and their arguments as they are executed.

       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 can be found in $-. The remaining arguments are positional parameters and are assigned, in order, to $1, $2, .... If no arguments are
       specified 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 specified names are marked for automatic export to the environment of subsequently executed commands. If no
       arguments are specified, variable names that have been marked for export during the current shell's execution are  listed.  Function  names
       are not exported.

   csh
       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 *'.

       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 specified 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,  sepa-
       rated  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.

   ksh
       The flags for the set built-in have meaning as follows:

       -A	    Array assignment. Unsets the variable name and assigns 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.

       -b	    Causes the shell to notify the user asynchronously of background job completions.

       -C	    Prevents  existing	files  from being overwritten by the shell's > redirection operator. The >| redirection operator overrides
		    this noclobber option for an individual file.

       -e	    If a command has a non-zero exit status, executes the ERR trap, if set, and exits. This mode is disabled  while  reading  pro-
		    files.

       -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  run  in  a  separate  process group and a line prints 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	    Reads commands and checks them for syntax errors, but does not execute them. Ignored for interactive shells.

       +o	    Writes the current option stettings to standard output in a format that is suitable for reinput to the shell as commands  that
		    achieve the same option settings.

       -o option    The option 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 does 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 operator > from truncating existing files. Requires the >| operator to truncate a file when
				  turned on. Same as -C.

		    noexec	  Same as -n.

		    noglob	  Same as -f.

		    nolog	  Does not save function definitions in history file.

		    notify	  Same as -b.

		    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 con-
				  trol 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  when-
	       ever  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      Sorts the positional parameters lexicographically.

       -t      Exits after reading and executing one command.

       -u      Treats unset parameters as an error when substituting.

       -v      Prints shell input lines as they are read.

       -x      Prints commands and their arguments as they are executed.

       -       Turns off -x and -v flags and stops examining arguments for flags.

       -       Does not change any of the flags. This option is 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 can 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 specified then the names and values of all variables are printed on the standard output.

       The  variables specified by the list of names are unassigned, that is, 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 specified by the list of names are unassigned, i.e., their values and attributes are erased. readonly vari-
       ables 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 specified names are marked for automatic export to the environment of subsequently-executed commands.

       When -p is specified, export writes to the standard output the names and values of all exported variables in the following format:

	 "export %s=%s
", name, value

       if name is set, and:

	 "export %s
", name

       if name is unset.

       The shell formats the output, including the proper use of quoting, so that it is suitable for reinput to the shell as commands that achieve
       the same exporting results, except for the following:

	   1.	  Read-only variables with values cannot be reset.

	   2.	  Variables that were unset at the time they were output are not reset to the unset state if a value is assigned to  the  variable
		  between the time the state was saved and the time at which the saved output is reinput to the shell.

       On this manual page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:

	   1.	  Variable assignment lists preceding the command remain in effect when the command completes.

	   2.	  I/O redirections are processed after variable assignments.

	   3.	  Errors cause a script that contains them to abort.

	   4.	  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  genera-
		  tion are not performed.

   ksh93
       set  sets  or  unsets  options and positional parameters. Options that are specified with a - cause the options to be set. Options that are
       specified with a + cause the option to be unset.

       set without any options or arguments displays the names and values of all shell variables in the order of the  collation  sequence  in  the
       current locale. The values are quoted so that they are suitable for input again to the shell.

       If  no  arguments are specified, not even the end of options argument --, the positional parameters are unchanged. Otherwise, unless the -A
       option has been specified, the positional parameters are replaced by the list of arguments. A first argument of -- is ignored when  setting
       positional parameters.

       For backwards compatibility, a set command without any options specified, whose first argument is - turns off the -v and -x options. If any
       additional arguments are specified, they replace the positional parameters.

       The options for set in ksh93 are:

       -a	      Set the export attribute for each variable whose name does not contain a . that you assign a  value  in  the  current  shell
		      environment.

       -A name	      Assign  the  arguments sequentially to the array named by name starting at subscript 0 rather than to the positional parame-
		      ters.

       -b	      The shell writes a message to standard error as soon it detects that a background job completes rather  than  waiting  until
		      the next prompt.

       -B	      Enable {...} group expansion. On by default.

       -C	      Prevents	existing  regular files from being overwritten using the > redirection operator. The >| redirection overrides this
		      noclobber option.

       -e	      A simple command that has a non-zero exit status causes the shell to exit unless the simple command is:

			  o	 contained in an && or || list

			  o	 the command immediately following if, while, or until

			  o	 contained in the pipeline following !

       -f	      Pathname expansion is disabled.

       -G	      Causes ** by itself to also match all sub-directories during pathname expansion.

       -h	      Obsolete. Causes each command whose name has the syntax of an alias to become a tracked alias when it is first encountered.

       -H	      Enable !-style history expansion similar to csh.

       -k	      This is obsolete. All arguments of the form name=value are removed and placed in the variable assignment list for  the  com-
		      mand. Ordinarily, variable assignments must precede command arguments.

       -m	      When  enabled,  the shell runs background jobs in a separate process group and displays a line upon completion. This mode is
		      enabled by default for interactive shells on systems that support job control.

       -n	      The shell reads commands and checks for syntax errors, but does not execute the command. Usually specified on command  invo-
		      cation.

       -o [option]    If  option is not specified, the list of options and their current settings is written to standard output. When invoked with
		      a + the options are written in a format that can be input again to the shell to restore the settings.  This  option  can	be
		      repeated to enable or disable multiple options.

		      The value of option must be one of the following:

		      allexport      Same as -a.

		      bgnice	     All background jobs are run at lower priorities.

		      braceexpand    Same as -B.

		      emacs	     Enables or disables emacs editing mode.

		      errexit	     Same as -e.

		      globstar	     Equivalent to -G.

		      gmacs	     Enables  or  disables gmacs. gmacs editing mode is the same as emacs editing mode, except for the handling of
				     CTRL-T.

		      histexpand     Same as -H.

		      ignoreeof      The interactive shell does not exit on end-of-file.

		      keyword	     Same as -k.

		      markdirs	     All directory names resulting from file name generation have a trailing / appended.

		      monitor	     Same as -m.

		      multiline      Use multiple lines when editing lines that are longer than the window width.

		      noclobber      Same as -C.

		      noexec	     Same as -n.

		      noglob	     Same as -f.

		      nolog	     This has no effect. It is provided for backward compatibility.

		      notify	     Same as -b.

		      nounset	     Same as -u.

		      pipefail	     A pipeline does not complete until all components of the pipeline have completed, and the exit status of  the
				     pipeline  is  the	value  of  the	last command to exit with non-zero exit status, or is zero if all commands
				     return zero exit status.

		      privileged     Same as -p.

		      showme	     Simple commands preceded by a ; are traced as if -x were enabled but not executed.

		      trackall	     Same as -h.

		      verbose	     Same as -v.

		      vi	     Enables or disables vi editing mode.

		      viraw	     Does not use canonical input mode when using vi edit mode

		      xtrace	     Same as -x.

       -p	      Privileged mode. Disabling -p sets the effective user id to the real user id, and the effective group id to the  real  group
		      id.  Enabling  -p  restores the effective user and group ids to their values when the shell was invoked. The -p option is on
		      whenever the real and effective user id is not equal or the real and effective group id is not equal. User profiles are  not
		      processed when -p is enabled.

       -r	      Restricted. Enables restricted shell. This option cannot be unset once enabled.

       -s	      Sort the positional parameters

       -t	      Obsolete. The shell reads one command and then exits.

       -u	      If enabled, the shell displays an error message when it tries to expand a variable that is unset.

       -v	      Verbose. The shell displays its input onto standard error as it reads it.

       -x	      Execution  trace. The shell displays each command after all expansion and before execution preceded by the expanded value of
		      the PS4 parameter.

       The following exit values are returned by set in ksh93:

       0     Successful completion.

       >0    An error occurred.

       For each name specified, unset unsets the variable, or function if -f is specified, from the current shell execution environment. Read-only
       variables cannot be unset.

       The options for unset in ksh93 are:

       -f    Where name refers to a function name, the shell unsets the function definition.

       -n    If  name  refers  to variable that is a reference, the variable name is unset rather than the variable it references. Otherwise, this
	     option is equivalent to the -v option.

       -v    Where name refers to a variable name, the shell unsets it and removes it from the environment. This is the default behavior.

       The following exit values are returned by unset in ksh93:

       0     Successful completion. All names were successfully unset.

       >0    An error occurred, or one or more name operands could not be unset

       export sets the export attribute on each of the variables specified by name which causes them to be in the environment of subsequently exe-
       cuted commands. If =value is specified, the variable name is set to value.

       If no name is specified, the names and values of all exported variables are written to standard output.

       export is built-in to the shell as a declaration command so that field splitting and pathname expansion are not performed on the arguments.
       Tilde expansion occurs on value.

       The options for export in ksh93 are:

       -p    Causes the output to be in the form of export commands that can be used as input to the shell to recreate the current exports.

       The following exit values are returned by export in ksh93:

       0     Successful completion.

       >0    An error occurred.

       On this manual page, ksh93(1) commands that are preceded by one or two + are treated specially in the following ways:

	   1.	  Variable assignment lists preceding the command remain in effect when the command completes.

	   2.	  I/O redirections are processed after variable assignments.

	   3.	  Errors cause a script that contains them to abort.

	   4.	  They are not valid function names.

	   5.	  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 field splitting and file name genera-
		  tion are not performed.

EXAMPLES

   csh
       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"

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       csh(1), ksh(1), ksh93(1), read(1), sh(1), typeset(1), attributes(5), environ(5)

SunOS 5.11							    20 Nov 2007 							    set(1)