title: How can I remove non-existing files from my git repo?
body: <p>I am abusing GIT to use it, locally, as an incremental backup solution. In part to teach me git, but in part to combat JPG and MP3 file corruption, which happens once in a blue moon.</p>
  
  <p>The repo gets huge, obviously.  I need to purge non-existent files from history.  (I have a lot of security videos that go into the system automatically, but also get deleted later, and I don't need a fully checked in video feed of my front yard in my .git folder.)</p>
  
  <p>This is a matter of abusing the tool in the "right" way -- I don't mind wasting a lot of space for the files I have; I don't mind a file having 100 versions if it's a file that exists.  But if it doesn't exist, I want it out of the repo, with no way to ever bring it back; erased from history completely.</p>