How do you fix a bad merge, and replay your good commits onto a fixed merge?

Question

I accidentally committed an unwanted file (filename.orig while resolving a merge) to my repository several commits ago, without me noticing it until now. I want

Answer 1

If you haven't committed anything since, just git rm the file and git commit --amend.

If you have

git filter-branch \
--index-filter 'git rm --cached --ignore-unmatch path/to/file/filename.orig' merge-point..HEAD

will go through each change from merge-point to HEAD, delete filename.orig and rewrite the change. Using --ignore-unmatch means the command won't fail if for some reason filename.orig is missing from a change. That's the recommended way from the Examples section in the git-filter-branch man page.

Note for Windows users: The file path must use forward slashes