As for how you can monitor your system resources, I would
suggest lsof1 for that. Use it with the -r option
while perl processes are created and killed, and you'll know whatever
stays open or not. With lsof you can also monitor
in reply to How aggressively does Perl clean up when you exit()?
And you'd need 'ps' or any of the Proc modules
(Proc, eg Proc::ProcessTable) to monitor memory usage. As stated elsewhere,
memory cleanup depends on your OS.
1 Assuming you are on *nix
Update: I also come across a mac os9 utility that
lists open files