* 0: OK
* 1: Generic error
* 10: Init failed because $GIT_DIR exists
* 11: Could not enter $GIT_WORK_TREE
* 12: No repository found
* 13: Required directory exists but is not a directory
* 14: Could not create directory
* 15: Could not create file
* 16: Potentially harmful operation aborted
* 17: Files that would be overwritten exist; fix manually

* 50: Could not create directory
* 51: Could not create file
* 52: Could not move directory
* 53: Could not move file

* 99: Error code reserved for actions that should never happen