Not too long ago I went through a process of changing my user in OS X to another name. It seemed to go smoothly enough. However many of my old applications are owned by an "_unknown" now. This is fine and dandy, except that every time I go to rename or move something in these places, it either has to authenticate or just tells me I'm not allowed. What would be a simple, effective way to change ownership on all files/folders tied to "_unknown" to my current user?