How can I undo git reset --hard HEAD~1?

Question

Is it possible to undo the changes caused by the following command? If so, how?

git reset --hard HEAD~1

Answer 1

It is possible to recover it if Git hasn't garbage collected yet.

Get an overview of dangling commits with fsck:

$ git fsck --lost-found
dangling commit b72e67a9bb3f1fc1b64528bcce031af4f0d6fcbf

Recover the dangling commit with rebase:

$ git rebase b72e67a9bb3f1fc1b64528bcce031af4f0d6fcbf