Hi, Brand new to regex. So I have a cli which runs a regex on users input, to make sure that only 0-9 and A-Z are accepted. It should strip everything else. My problem is that when you press control-Z (on Windows; I have not yet tested this on linux, and I will, but I would like this to be compatible with both OS's) it loops infinitely saying invalid data (because of the next method call, which decides what to do based on your input). So, here is the input code. Is there a way I can ensure that control commands are stripped, here? public function getSelection() { $choice = $this->validateChoice(trim(strtoupper(fgets(STDIN)))); return $choice; } private function validateChoice($choice) { $choice = ereg_replace("/[^0-9A-Z]/","",$choice); return $choice; } I have tried a ton of different things to try and fix this. Tried /\c.|[^0-9A-Z]/, and many variations of \c and the [^0-9A-Z], to no avail. I also tried using both preg_replace() as well as ereg_replace(). I spent a lot of time on the regex section of the PHP manual, but I am not finding anything. Any advise on how to accomplish this? Thanks, Jesse Hazen