I booted up my mac and found a file called 'devnull' in my user folder, which was 13gb. I tried opening it in textedit to see what it was but it kept freezing, as well as finder. I tried to delete it but finder didn't seem to want to. I finally was able to eliminate it using rm ~/devnull It's gone now, but now I notice finder is crashing quite often. What is this "devnull" file, and is it bad that I deleted it??