use strict ;
use Getopt::Long;

my ($username,$password,$group);
my $err_msg='';

GetOptions('u=s' => \$username,'g=s'=> \$group,
           'p=s'=>\$password);

$err_msg.="missing -u username\n" unless $username;
$err_msg.="missing -g group\n" unless $group;
$err_msg.="missing -p password\n" unless $password;

die "$err_msg" if $err_msg;