[phone_book]

I love how this got 4 different answers.

[peteradio]

2 answers the same and rolling back all files. 1 answer for rolling back single file. 1 non-solution.

The OP has a poorly defined use case for "undo" (which commit? all files or one?) and can easily wrap whichever suits their need in an alias.

[pxmpxm]

The question was intentionally crafted for that effect :)