http://www.perlmonks.org?node_id=48948

Q&A > programs and processes > Can Perl remain persistent for scripts just like mod_perl does for apache? - Answer contributed by ichimunki

What would be the advantage to this? The interpretation of the script is the slow part of start-up, if I'm not mistaken.

If you want your script to stay in memory run the whole thing from inside a while (1) loop, with an explicit option to exit somewhere inside the loop.