open my $WHOIS, "jwhois x.x.x.x 2>&1 |";
my $s = IO::Select->new($WHOIS);

while (my @ready = $s->can_read) {
    for my $fh (@ready) {
        if ($fh == $WHOIS) {
            my $buf = <$fh>;
            if ($buf) {
                print $buf;
            }
            else {
               close($fh);
            }
        }
    }
}