I may be misinterpreting the question, but aren't runtime errors things that cause the whole program to die? So, either you need to catch them via eval (and thus use the $@ variable), or you may be able to catch them on the way out via %SIG, although I'm not sure that's a good idea...

You might want to scan through perlvar which lists all of the Perl special variables. You'll probably be surprised how many things you can change with some special variable, and even if you don't need them now, you may remember that they exist later. (I also recommend the same scan of perlfunc at least once, just so you know what's there.)

Personally, I keep a copy of The Perl Pocket Reference (okay, 4 copies, I don't know how I keep acquiring them) next to my desk. I like paper references. :)