How to modify a specified commit?

Question

I usually submit a list of commits for review. If I have the following commits:

1. HEAD
2. Commit3
3. Commit2

Answer 1

Automated interactive rebase edit followed by commit revert ready for a do-over

I found myself fixing a past commit frequently enough that I wrote a script for it.

Here's the workflow:

1. git commit-edit 
   

   This will drop you at the commit you want to edit.

2. Fix and stage the commit as you wish it had been in the first place.

   (You may want to use git stash save to keep any files you're not committing)

3. Redo the commit with --amend, eg:

   git commit --amend
   

4. Complete the rebase:

   git rebase --continue
   

For the above to work, put the below script into an executable file called git-commit-edit somewhere in your $PATH:

#!/bin/bash

set -euo pipefail

script_name=${0##*/}

warn () { printf '%s: %s\n' "$script_name" "$*" >&2; }
die () { warn "$@"; exit 1; }

[[ $# -ge 2 ]] && die "Expected single commit to edit. Defaults to HEAD~"

# Default to editing the parent of the most recent commit
# The most recent commit can be edited with `git commit --amend`
commit=$(git rev-parse --short "${1:-HEAD~}")
message=$(git log -1 --format='%h %s' "$commit")

if [[ $OSTYPE =~ ^darwin ]]; then
  sed_inplace=(sed -Ei "")
else
  sed_inplace=(sed -Ei)
fi

export GIT_SEQUENCE_EDITOR="${sed_inplace[*]} "' "s/^pick ('"$commit"' .*)/edit \\1/"'
git rebase --quiet --interactive --autostash --autosquash "$commit"~
git reset --quiet @~ "$(git rev-parse --show-toplevel)"  # Reset the cache of the toplevel directory to the previous commit
git commit --quiet --amend --no-edit --allow-empty  #  Commit an empty commit so that that cache diffs are un-reversed

echo
echo "Editing commit: $message" >&2
echo