There are a couple ways to interpret this question. I will assume you mean you would like the elements of each array that are excluded from the union of the two.

#!/usr/bin/perl
use strict;
use warnings;

my @array1 = qw(a b c e);
my @array2 = qw(a b c d);

my %hash;
for my $key (@array2) {
    $hash{$key}++;
}

for my $key (@array1) {
    print "Fail #1: $key\n" unless $hash{$key}--;
}


for my $key (keys %hash) {
    print "Fail #2: $key\n" if $hash{$key} > 0;
}
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For other related solutions, check out How do I compute the difference of two arrays? How do I compute the intersection of two arrays? in perlfaq4