Thanks for the suggestion, but unfortunately something that requires backticks or something like system() tends to be exactly the sort of thing (other than non-core modules) I wanted to avoid. It really hurts portability.

Your assumption about using a Unixlike OS is correct -- I'm on FreeBSD -- but I don't want to limit the usefulness of this script to OSes that include the standard unixy core utilities. It's bad enough requiring a specific language interpreter (Perl's, specifically) to run the thing.