I am trying to rename a file to have different capitalization from what it had before:
git mv src/collision/b2AABB.js src/collision/B2AABB.js fatal: destinat
File names under OS X are not case sensitive (by default). This is more of an OS problem than a Git problem. If you remove and readd the file, you should get what you want, or rename it to something else and then rename it back.