use HTTP::Request;
use HTTP::Request::Common qw(GET POST);
use HTTP::Cookies;
use LWP::UserAgent;

my $browser=new LWP::UserAgent;

my $cookies=new HTTP::Cookies( file=>"/tmp/cookies.txt", autosave=>1, ignore_discard=>1);
$browser->cookie_jar($cookies);

$req = POST 'http://localhost/wiki/index.php?title=Special:Userlogin&action=submitlogin&wpName=readuser&wpPassword=letmein';
$response=$browser->request($req);