use Getopt::Long ();

sub usage {
   my $message = $_[0];
   if (defined $message && length $message) {
      $message .= "\n"
         unless $message =~ /\n$/;
   }

   my $command = $0;
   $command =~ s#^.*/##;

   print STDERR (
      $message,
      "usage: $command -u username [-p password] -s hostname:port\n" .
      "       ...\n" .
      "       ...\n" .
      "       ...\n"
   );

   die("\n")
}


my $user;
my $passwd;
my $host;
my $port;

Getopt::Long::GetOptions(
   'u=s' => \$user,
   'p=s' => \$passwd,
   's=s' => sub {
      local *_ = \$_[1];
      /^([^:]+):(\d+)$/
      or die("Invalid format for option s.\n");
      $host = $1;
      $port = $2;
   },
)
or usage("Invalid commmand line options.");
 
usage("The user name must be specified.")
   unless defined $user;

usage("The server hostname and port must be specified.")
   unless defined $host;

if (!defined $passwd) {
   # Prompt for password here...
}