Ok, here's my deal. I have one official iTunes library with music files on my Mac and then I have a folder on my backup drive with iTunes music files. These two directories are mostly the same but they each have a few differences. I want to backup my iTunes music onto that backup drive but I need to make sure that I get all the music from my Mac and the backup drive. The folders are slightly different and I don't want to lose any music. Whats the best way to do this? Should I just run an rsync command to merge the two folders together into a third folder and then use that as my backup?