Allows you to invoke Unix shell utilities as if they were Perl subroutines. Arguments (including switches) are passed to the utilities as strings:
use Shell qw(date cp ps); # list shell commands you want to use $date = date(); # put the output of the date(1) command into $date cp("-p" "/etc/passwd", "/tmp/passwd"); # copy password file to a tmp file print ps("-ww"); # print the results of a "ps -ww" command