cpanlist.pl

#!/usr/bin/perl

use strict;
use warnings;
use ExtUtils::Installed;

local $\ = "\n";

my $ptn = shift @ARGV || '';
my @modules = ExtUtils::Installed->new->modules;

unless ($ptn) {
    print join "\n" => sort @modules;
}
else {
    my $regex = qr{$ptn};
    print join "\n" => sort grep { m|$regex|xoi } @modules;
}