That is a known bug in 5.00550. Either an upgrade or a downgrade will fix it. - Larry Wall

...Then you start building things like the Berlin wall to keep people inside your community. In anthropological terms, that's tribalism. A tribal Perl programmer might say, "If you leave the Perl tribe to go and join the Python tribe, we will hunt you down, cook you, and eat you." Or if you join the Ruby tribe, you will explode. By and large, I am not in favor of tribalism. Except for my tribe, of course.

That's a valid argument. I just don't think it's valid enough.

Does the same as the system call of that name. If you don't know what it does, don't worry about it.