The set Command

Besides manipulating Korn shell options, the set command can be used to display a list of your local and exported variables.

					$ set
					EDITOR=vi
					ENV=${HOME:—.}/.env
					FCEDIT=/bin/ed
					HOME=/home/anatole
					LOGNAME=anatole
					MAILCHECK=600
					PATH=:/usr/bin:/usr/ucb:/usr/5bin
					PPID=180
					. . .
				

It can also be used to "manually" reset positional parameters. For example:

					$ set X Y Z
				

would set $1 to X, $2 to Y, $3 to Z, and $# to 3:

					$ print $1 $2 $3 $#
					X Y Z 3
				

The positional parameters $@ and $* would be set X Y Z:

					$ print $*
					X Y Z
					$ print $@
					X Y Z
				

The $* and $@ parameters are basically the same, except for the way they are expanded when surrounded with double quotes. The positional parameters in $@ are interpreted as separate strings, while in the $*, they are interpreted as a single string. Using $@, the wc command counts three separate strings

					$ print "$@" | wc —w
					3
				

while with $*, only one string is counted:

					$ print "$*" | wc —w
					1
				

To manually set positional parameters that begin with the – character, use the set – command.

					$ set — —X —Y —Z
					$ print — $* 
—X —Y —Z
				

All the positional parameters can be unset with the set –– command:

					$ set A B C
					$ print $*
					A B C
					$ set — —
					$ print $*
					$