How to revert an unnecessary “git reset HEAD~1”

Question

After running git reset HEAD~1, I noticed that actually there was nothing else to do and the commit was fine. Is there a way to revert this command?

Answer 1

Even easier (if you haven't done any other operations):

git reset ORIG_HEAD

ORIG_HEAD is the previous state of HEAD.

More details about HEAD vs. ORIG_HEAD are in the answer to this SO question.