What you want to do is to specify the sha1 of the commit you want to restore to. You can get the sha1 by examining the reflog (git reflog) and then doing

git reset --hard <sha1 of desired commit>

But don't wait too long... after a few weeks git will eventually see that commit as unreferenced and delete all the blobs.

The answer is hidden in the detailed response above, you can simply do:

$> git reset --hard HEAD@{1}

(See the output of git reflog show)

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

As far as I know, --hard will discard uncommitted changes. Since these aren't tracked by git. But you can undo the discarded commit.

$ git reflog

will list:

b0d059c HEAD@{0}: reset: moving to HEAD~1
4bac331 HEAD@{1}: commit: added level introduction....
....

where 4bac331 is the discarded commit.

Now just move the head to that commit:

$ git reset --hard 4bac331

If you're really lucky, like I was, you can go back into your text editor and hit 'undo'.

I know that's not really a proper answer, but it saved me half a day's work so hopefully it'll do the same for someone else!

In most cases, yes.

Depending on the state your repository was in when you ran the command, the effects of git reset --hard can range from trivial to undo, to basically impossible.

Below I have listed a range of different possible scenarios, and how you might recover from them.

All my changes were committed, but now the commits are gone!

This situation usually occurs when you run git reset with an argument, as in git reset --hard HEAD~. Don't worry, this is easy to recover from!

If you just ran git reset and haven't done anything else since, you can get back to where you were with this one-liner:

git reset --hard @{1}

This resets your current branch whatever state it was in before the last time it was modified (in your case, the most recent modification to the branch would be the hard reset you are trying to undo).

If, however, you have made other modifications to your branch since the reset, the one-liner above won't work. Instead, you should run git reflog <branchname> to see a list of all recent changes made to your branch (including resets). That list will look something like this:

7c169bd master@{0}: reset: moving to HEAD~
3ae5027 master@{1}: commit: Changed file2
7c169bd master@{2}: commit: Some change
5eb37ca master@{3}: commit (initial): Initial commit

Find the operation in this list that you want to "undo". In the example above, it would be the first line, the one that says "reset: moving to HEAD~". Then copy the representation of the commit before (below) that operation. In our case, that would be master@{1} (or 3ae5027, they both represent the same commit), and run git reset --hard <commit> to reset your current branch back to that commit.