open OUT, ">filename" or die "can't open file for writing: $!";

    while (<DATA>) {
        my ($one, $two) = m|##(\d{4,4})## *(\d{4,4})|;
        print OUT $_ unless $one == $two;
    }

    __DATA__
    REG-NZL-PUB.1981-263 ##1981## 19810922