#! perl -slw use strict; sub times7 { my $number = shift or die "no number"; return $number*7; } print "times7( $_ ) returned:", times7( $_ ) for 1, 2, 3, 0; __END__ P:\test>junk times7( 1 ) returned:7 times7( 2 ) returned:14 times7( 3 ) returned:21 no number at P:\test\junk.pl line 5.