How can I undo the last commit?
Note the --soft flag: this makes sure that the changes in undone revisions are preserved.
After running the command, you'll find the changes as uncommitted local modifications in your working copy.
$ git reset --soft HEAD~1
If you don't want to keep these changes, simply use the --hard flag.
Be sure to only do this when you're sure you don't need these changes anymore.
$ git reset --hard HEAD~1