Trying to get a regex for any string that matches `view.php` with the GET variable `file` with as value `[a-zA-Z0-9_]*`. FYI, I need to rewrite this URL to `/file/value`

What I did but didn't work: `^view.php\?.*?(&|\?)file=([a-zA-Z0-9_]*).*$`

What does work?