#!/usr/bin/perl -l

use strict;
use warnings;
use List::Compare;

my (@Llist) = qw(abc def 121 xyz);
my (@Rlist) = qw(def 121);

my $lc = List::Compare->new( \@Llist, \@Rlist );

my (@sdiff) = $lc->get_symmetric_difference;
foreach my $sdiff(@sdiff) {
     print $sdiff;
}