regex

Im expecting a string like foo.png. Im trying to replace 'foo' with another value that I have. Im trying this -> $file = preg_replace('/([a-z][0-9]-_*)(.[a-z]{3,4})/i', $new_file . "$2", $_FILES['upload']['name']); The second regex group works ok, its the first one I cannot figure out. It is supposed to contain alpha numeric characters and '_' and '-'. Thanks for any input. -- Gerard Samuel http://www.trini0.org:81/ http://dev.trini0.org:81/