my %differences = ();
foreach (keys %hash1) {
    $differences{$_}= [$hash1{$_}, $hash2{$_}] if $hash1{$_} ne $hash2{$_};
};
foreach (keys %hash2) {
    $differences{$_}= [$hash1{$_}, $hash2{$_}] if $hash1{$_} ne $hash2{$_};
};