Perl != CGI, Biker. :-)

And to the original poster: I doubt that it's particularly easy to do, and it's certainly platform dependent. You'd pretty much have to go through the window system: at best, you'd be able to ask "which process has the input focus?"; at worst, you'd have to have the target process send yours a message when it receives (and loses) focus.

I hope there's an easier, cleaner way, but I don't know of one.

--
The hell with paco, vote for Erudil!
:wq