Korn Shell. Unix and Linux Programming Manual, Third Edition

   

Korn Shell: Unix and Linux Programming Manual, Third Edition, The

By Anatole Olczak

Table of Contents
Chapter 9.  Miscellaneous Commands

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 ?/span> character, use the set ?/span> command.

$ set ? X Y Z $ print ?$* ?span>X Y Z

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

$ set A B C $ print $* A B C $ set ??/span> $ print $* $


       
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