you have to say my $opt_u, or the compiler will spit an error -- or you could say (assuming main package) $MAIN::opt_u and be gone with it.

This is because use strict requires you're variables to be declared -- or, as I think on it, you could say use vars qw/$opt_u ... others here.../; (hey, TMTOWTDI :)

May I suggest, however, that (I assume you're using a GetOpt:: module here) you don't let the GetOpt module assign $opt_<whatever>, but instead pass it a hash reference. This way you can say $opts->{<whatever>} and be done with it.