Beatnik's source filter - Filter::NumberLines - will number the lines *and* maintain the runability of said lines...

#!/usr/bin/perl -w
use lib './perllibs';
use Filter::NumberLines;
004:    use strict;
005:
006:    print "I like Jellybeans\n";
[download]

Not only were the 004-??? line number put in there for me, but the program runs correctly just like that with the line numbers included. Very clever stuff.

-Blake