git-touch - change HEAD commit timestamps
git touch [<argument for date command>]...
This command updates the timestamps (author and commit dates) of the HEAD commit. By default it sets them to the current time.
Any extra argument is passed on as is to date to choose the new timestamps. Setting an argument to change the format of the output date would probably break everything.
git touch exits on failure when git rewrite-commit (which does the actual job) does.
git rewrite-commit(1)