use strict;
use warnings;
use CGI;
use CGI::Cookie;

my $c = new CGI::Cookie(
  -name    =>  'session_id',
  -value   =>  '23423',
  -domain  =>  '.testdomain.com', 
  -path    =>  '/testfolder',
  -expires =>  '+30m',
);
print header(-cookie=>$c);

#--- Rest of Script