But in passing it may be worthwile to remind a cheap alternative that would yield the absolute maximum of portability: editor macros or templates.

Seconded. Whenever I start a perl file, I start with a macro that loads one of three templates for me (one for programs, one for non-OO modules, and one for OO modules). They include things like a she-bang line, use strict, use/no warnings, modules I often use with a '#' in front of the use so I don't pay a price when I don't need them, but can enable them by just deleting a single character.

And Perl isn't the only language I use templates for. I also have them for C, awk, FORTRAN, and Pascal. Not to mention tons of (retired) templates for all kinds of projects.