$ cat x use strict; use warnings; use FindBin; use File::Basename; is_loaded('FindBin'); is_loaded('Data::Dumper'); is_loaded('File::Basename'); sub is_loaded { my ($pkg) = @_; (my $file = $pkg) =~ s/::/\//g; $file .= '.pm'; my @loaded = grep { $_ eq $file } keys %INC; print "package $pkg is " . (@loaded ? '' : 'NOT ') . "loaded\n"; return } $ perl x package FindBin is loaded package Data::Dumper is NOT loaded package File::Basename is loaded