my @serv = getservbyname(my $serv = $rport, 'tcp');
        $rport = $serv[2];
        croak "Can't map service name '$serv' to port number"
            unless defined $rport;

##</code><code>##

        my @serv = getservbyname(my $serv = $rport, 'tcp');
        $rport = $serv[2] || 22;

##</code><code>##

ssh 22/tcp  # Secure Shell Login