Ammend Old Commits with file changes

.bashrc

git-amend-old() (
      # Stash, apply to past commit, and rebase the current branch on to
of the result.
      # For Gerrit.
https://stackoverflow.com/questions/1186535/how-to-modify-a-specified-commit/53$
      current_branch="$(git rev-parse --abbrev-ref HEAD)"
      apply_to="$1"
      git stash
      git checkout "$apply_to"
      git stash apply
      git add -u
      git commit --amend --no-edit
      new_sha="$(git log --format="%H" -n 1)"
      git checkout "$current_branch"
      git rebase --onto "$new_sha" "$apply_to"
    )

export -f git-amend-old

Usage.md

Usage:

1. Modify the file with the change you want
2. Call git-amend-old <sha>, replacing <sha> with the commit sha you want the change to apply to