That's pretty cool. I've been using something a bit similar for a while too, just to run my changes through PEP8 (http://tech.myemma.com/python-pep8-git-hooks/). Mine uses the output of `git status --porcelain` to get the changed files, and writes them to a temporary directory with `git show`. Similar result to yours, but I think I like your `git diff` way better.