#!/usr/bin/perl -l

use strict;
use warnings;

my @file1=qw/foo bar baz/;
my @file2=qw/fred bar barney/;

my %saw;
$saw{$_}++ for @file1, @file2;

print <<"EOT"
\@file1 only: (@{[ grep $saw{$_}==1, @file1 ]})
\@file2 only: (@{[ grep $saw{$_}==1, @file2 ]})
common: (@{[ grep $saw{$_}==2, @file2 ]})
EOT

__END__