Create and Apply Patches using GIT DIFF and APPLY

Create Patch:
git diff PATH/TO/SOURCE.php > PATH/SAVE_patch.diff

Apply patch
git apply PATH/SAVE_patch.diff

Reversing patches

To revert a patch simplt add the option -R
Example:
git apply -R PATH/SAVE_patch.diff

More Info : http://www.thegeekstuff.com/2014/03/git-patch-create-and-apply/