Like it or not, modules are the best way. Modules need not be difficult; you probably need only a small fraction of the many options available to a module author. To get started, see tachyon's Simple Module Tutorial, including the other monks' comments at the bottom. If the tutorial is too simple, try perlman:perlmod. If too complex, try my skeleton code below. I have pared it down to the bare essentials for illustration only; it runs correctly, but is missing the seat-belts (use strict) and air-bags (use warnings), so don't take it out of the parking lot!

Use h2xs -n Common_Code -AX to generate a real module template once you are more comfortable with how a module works.

# this is in file Common_Code.pm
package Common_Code;
sub log_debug_message
{
    print "DEBUG: I see ", join(", ", @_), ".\n";
}

1;
[download]

#!/usr/bin/perl
use Common_Code;

my( $a1, $b2, $c3 ) = qw( red blue green );

Common_Code::log_debug_message( $a1, $b2, $c3 );
[download]

DEBUG: I see red, blue, green.
[download]