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 sockets etc.

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.

hth,

Jeroen

¹ Assuming you are on *nix

Update: I also come across a mac os9 utility that lists open files