#!/usr/bin/perl

use strict;
use warnings;
use Set::Scalar;
use Tie::File;

tie my @x, "Tie::File", $ARGV[0] or die $!;
tie my @y, "Tie::File", $ARGV[1] or die $!;

my $vorher  = Set::Scalar->new(@x);
my $nachher = Set::Scalar->new(@y);

my @db = $nachher->difference($vorher)->members; # hinzugekommen
my @fs = $vorher->difference($nachher)->members; # weggefallen

foreach my $dbitem (@db) {
    print "> ", $dbitem, "\n";
}

foreach my $fsitem (@fs) {
    print "< ", $fsitem, "\n";
}