my $url = "[URL=http://www.google.de;]http://www.google.de";[/URL]
my $name = "q";
my $value = "linux";
my $button = "btnG";

use WWW::Mechanize;

my $agent = WWW::Mechanize->new(autocheck=>1);
$agent->proxy(['http', 'https'], '[URL=http://meinProxy]http://meinProxy[/URL]:8080/');

$agent->get($url);
$agent->field($name, $value);
$agent->click($button);
print $agent->content;