A commonly asked question by sysadmins is how to list all perl modules - installed and known to perl - on a system.
This is how i do it:
perl -MFile::Find=find -MFile::Spec::Functions -Tlwe 'find { wanted => sub { print canonpath $_ if /\.pm\z/ }, no_chdir => 1 }, @INC;'
I took this somewhere from perlmonks a long time ago.