while (my $line = <$rulesFH>) {

    if ($. == 1) {
        # Remove Byte Order Mark if it's there
        use Encode;
        my $octets = encode("utf8", $line);
        $octets =~ s/^\x{ef}\x{bb}\x{bf}//;
        $line = decode("utf8", $octets);
    }

    # rest...
}