That method is awfully neat, but my perl skills are not so I'll hit you with a follow-up question.

So this iterates through the file and, if a random number from 0 to the current line number is less than 1, selects the current line, overwriting previous choices? So, in my case, I'd just keep a count variable for how many elements I've been through and use that in place of $.?

I'm going to have to check out the proof of that, it is really interesting that everything evens out (i.e. the first elements have a high chance of being overwritten, the latter elements have a high chance of just not being picked, and it all balances out to a random selection.) Thanks for pointing me to that FAQ entry!