perl -MDevel::Symdump -E "package A{sub asub{1}}package B::B{sub bsub{1}};; $sym=Devel::Symdump->rnew('main'); for $p($sym->packages){ for ($sym->functions($p)){die qq($_ found in package $p) if $_ eq $p.'::'.$ARGV[0]} }" bsub B::B::bsub found in package B::B at -e line 1.