codeigniter redirect back with flash data code example

Example: redirect back in codeigniter

This should help :
http://www.codeigniter.com/user_guide/libraries/user_agent.html

$this->load->library('user_agent');
if ($this->agent->is_referral()){
    echo $this->agent->referrer();
}

or straight PHP:

redirect($_SERVER['HTTP_REFERER']);