[otrs] Help.Retriving user name who is logged in

Hi all.. i want to display a link in "Search" which will first check that if a logged user has admin permissions or not. If HE/She has admin rw permissions then only he can view that link in search page otherwise not... It is same theme as that of "Admin link" in index.pl/..It is displayed if he has admin permissions... But still im not getting how to retrive logged username while clicking on search link...then how to check it that it has admin permission or not... Plz help me..