$ssh->auth_password($ssh_user,$ssh_pass);
if ($ssh->auth_ok()) {
        my $session = $ssh->channel();
        $session->exec('uname -a');
        while ($session->read(my $answer,1024)) {
                print $answer;
        }
        $session->close();
        $ssh->disconnect();
}
else {
        print STDERR "authentication failed\n";
}