How to undo "git commit --amend" done instead of "git commit"

Question

I accidentally amended my previous commit. The commit should have been separate to keep history of the changes I made to a particular file.

Is there a way to undo that last commit? If I do something like git reset --hard HEAD^, the first commit also is undone.

(i have not yet pushed to any remote directories)

Answer 1

You can always split a commit, From the manual

• Start an interactive rebase with git rebase -i commit^, where commit is the commit you want to split. In fact, any commit range will do, as long as it contains that commit.
• Mark the commit you want to split with the action "edit".
• When it comes to editing that commit, execute git reset HEAD^. The effect is that the HEAD is rewound by one, and the index follows suit. However, the working tree stays the same.
• Now add the changes to the index that you want to have in the first commit. You can use git add (possibly interactively) or git-gui (or both) to do that.
• Commit the now-current index with whatever commit message is appropriate now.
• Repeat the last two steps until your working tree is clean.
• Continue the rebase with git rebase --continue.

Answer 2

use the ref-log:

git branch fixing-things HEAD@{1}
git reset fixing-things

you should then have all your previously amended changes only in your working copy and can commit again

to see a full list of previous indices type git reflog

Answer 3

What you need to do is to create a new commit with the same details as the current HEAD commit, but with the parent as the previous version of HEAD. git reset --soft will move the branch pointer so that the next commit happens on top of a different commit from where the current branch head is now.

# Move the current head so that it's pointing at the old commit
# Leave the index intact for redoing the commit
git reset --soft HEAD@{1}

# commit the current tree using the commit details of the previous
# HEAD commit. (Note that HEAD@{1} is pointing somewhere different from the
# previous command. It's now pointing at the erroneously amended commit.)
git commit -C HEAD@{1}