Personally, I would find it COST efficient to put all my Perl utilities on a USB-keyring-drive, rather than spend the time to learn "arcane" shell syntax.

I know this has already been discussed (what with all the crawling around under desks) but I'd like to point out that I do not have easy physical access to most of the computers I use due to them being mounted in racks two floors below my office, and occasionally in other buildings. Using any form of portable media is pretty much a non-starter, so I would need to get any tools I need over the network or use those that are installed already.

That said, I have a load of tools on shared filesystems that can be accessed from most hosts, so usually it doesn't matter.