Check out the module List::Compare.

#copied from the documentation
use List::Compare;

my @Llist = qw(abel abel baker camera delta edward fargo golfer);

my @Rlist = qw(baker camera delta delta edward fargo golfer hilton);

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

#get_unique() 
#Get those items which appear (at least once) only in the first list.

    @Lonly = $lc->get_unique;
    @Lonly = $lc->get_Lonly;    # alias
#get_complement() 
#Get those items which appear (at least once) only in the second list.

    @Ronly = $lc->get_complement;
    @Ronly = $lc->get_Ronly;            # alias
[download]