I am just wondering is there any way to find duplicate files on my Mac? When I download something from "torrent", some unnecessary files also download along with the main file with .dat extension. I want to delete all of these .dat files at one time. I currently have a lot of these files on my computer & they are stored in many different directories. It would be a lot of work to delete them one by one. Thus, are there any free apps to do that job or some way I can find & delete them?