How to amend several commits in Git to change author

Question

I have made a series of commits in Git and I realise now that I forgot to set my user name and user email properties correctly (new machine). I have not yet pushed these commits to my repository, so how can I correct these commits before I do so (only the 3 latest commits on the master branch)?

I have been looking at git reset and git commit -C <id> --reset-author, but I don't think I'm on the right track.

Maes

Another reason you might want to change the email property is this github error: remote: error: GH007: Your push would publish a private email address. ... ` ! [remote rejected] master -> master (push declined due to email privacy restrictions)`. – Autocrat

Also see https://mcmap.net/q/12496/-how-do-i-change-the-author-and-committer-name-email-for-multiple-commits/1340631. – Betsybetta

Answer 1

Warning: now deprecated in favor of filter-repo.

Rebase/amend seems inefficient, when you have the power of filter-branch at your fingertips:

git filter-branch --env-filter 'if [ "$GIT_AUTHOR_EMAIL" = "incorrect@email" ]; then
     GIT_AUTHOR_EMAIL=correct@email;
     GIT_AUTHOR_NAME="Correct Name";
     GIT_COMMITTER_EMAIL=$GIT_AUTHOR_EMAIL;
     GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"; fi' -- --all

(split across lines for clarity, but not necessary)

Be sure to inspect the result when you're done, to make sure that you didn't change anything you didn't mean to!

Berthold

mind explaining this a bit more? not sure what filter branch is – Lusk

@maxpleaner git filter-branch --help is pretty straightforward :) – Screening

see also help.github.com/articles/changing-author-info, which also adds --tag-name-filter cat to the filter-branch in order to migrate tags to the new history. It also uses --branches --tags instead of --all, which only rewrites branch and tag history and leaves other refs alone (though that probably doesn't make much of a difference unless e.g. you're using git-notes) – Fonteyn

Note that it's important to use single quotes and not backticks around the command! – Noyes

to perform this on just the last two commits, I replaced -- --all with HEAD~1..HEAD – Lille

It works in local branch but when I am trying to push in origin I cannot. When I am trying to push, git is telling me to pull. When I am pulling I am getting the following error: "fatal: refusing to merge unrelated histories" – Poundfoolish

@Lille last two commits is HEAD~2..HEAD – Koal

@Koal I'm pretty sure that would yield the last 3 commits... HEAD, HEAD-1, and HEAD-2... that's 3 total – Lille

@Lille How many logs are shown if you do git log HEAD~2..HEAD ? – Koal

Remember to use git push -f afterwards to push the changes to the origin. – Tynes

The git filter-branch command now comes with a warning, and filter-repo (which is third-party) is recommended instead: github.com/newren/git-filter-repo. The alternative command would be along the lines of echo '<correct@email> <incorrect@email>' > .mailmap ; git filter-repo --use-mailmap. – Pietro

And don't forget to force the push git push --force – Removed

From the docs: 'WARNING! The rewritten history will have different object names for all the objects and will not converge with the original branch. You will not be able to easily push and distribute the rewritten branch on top of the original branch. Please do not use this command if you do not know the full implications, and avoid using it anyway, if a simple single commit would suffice to fix your problem. (See the "RECOVERING FROM UPSTREAM REBASE" section in git-rebase[1] for further information about rewriting published history.)'. Careful using --all! – Customs

Added an answer that uses filter-repo as recommended by git. – Mohr

Submitted an edit to warn about this: stackoverflow.com/suggested-edits/5320642 – Etoile

Answer 2

The interactive rebase approach is pretty nice when used in conjunction with exec. You can run any shell command against a specific commit or all commits in the rebase.

First set your git author settings

git config --global user.name "John Doe"
git config --global user.email [email protected]

Then to reset the author for all commits after the given BASE_SHA:

git rebase -i BASE_SHA -x \
  "git commit --amend --author 'John Doe <[email protected]>' -CHEAD"

This will pop up your editor to confirm the changes. All you need to do here is save and quit and it will go through each commit and run the command specified in the -x flag.

Trader

Thank you for introducing me to the -x option. Its pretty awesome! for the -i option I used HEAD~4 to fix my email address on my last 4 commits. worked like a charm. – Lorusso

This is much simpler than filter-branch if you just want to fix your last commits :). Note however, that this changes the timestamp of the commits. – Geek

As filter-branch is not that straight-forward, I also give my love to this one. Almost everything you usually do messing up your history is related to rebase -i, and this option fits this scheme perfectly. – Quadriga

To change the author but maintain the original timestamps, use git rebase -i YOUR_SHA -x "git commit --amend --author 'New Name <[email protected]>' -CHEAD" – Junker

This did not work for me. tried both the short and the long sha for the commit I wanted changed and it remained unchanged when I ran git log – Cicada

Just tried the second version (the one that keeps the original timestamps) and worked like a charm. Thank you so much! This should definitely be the accepted answer – Shortstop

@Cicada git log also showed old authorship for me, but git status correctly identified new commits and after force push they were as I intended. – Karyotype

To rebase all commits including the root use: git rebase -i --root … instead of passing a SHA. – Beaudoin

Thank you so much! git rebase -i YOUR_SHA -x "git commit --amend --author 'New Name <[email protected]>' -CHEAD" Worked like a charm! – Centurial

I was confused by "all you need to do is save and quit" since there was no "Save" option. For me, just ctrl-X to exit was all I had to do, and it executed correctly. – Minelayer

If you're a Windows user and the command opens the changes in vim, press Esc Z Z to save and quit. (Note the capital Zs) – Dreary

Just tried @Junker answer but the original timestamps are not maintained (you can check it here github.com/oncet/coel/commits/temp). Using git 2.25.1. – Isatin

@Isatin Same for me (git version 2.28.0.windows.1) – Gemma

To amend while keeping the date: git rebase -i YOUR_SHA -x 'git commit --amend --reset-author --no-edit --date="$(git log -n 1 --format=%aD)"' – Delfinadelfine

what is my SHA? – Halfprice

Answer 3

To change the author only for the last commit:

git commit --amend --author 'Author Name <[email protected]>' --no-edit

Suppose you only want to change the author for the last N commits:

git rebase -i HEAD~4 -x "git commit --amend --author 'Author Name <[email protected]>' --no-edit"

Change the committer as well:

as noted by @sshine and @Hermann.Gruber, the previous commands change the author only. To change the committer as well, you can use the solution proposed by @Hermann.Gruber:

git rebase -i HEAD~4 -x "GIT_COMMITTER_NAME='Author Name' GIT_COMMITTER_EMAIL='[email protected]' git commit --amend --author 'Author Name <[email protected]>' --no-edit"

NOTES

• the --no-edit flag makes sure the git commit --amend doesn't ask an extra confirmation
• when you use git rebase -i, you can manually select the commits where to change the author,

the file you edit will look like this:

pick 897fe9e simplify code a little
pick abb60f9 add new feature
exec git commit --amend --author 'Author Name <[email protected]>' --no-edit
pick dc18f70 bugfix

Staub

for all commits from root. git rebase -i --root UPTO_COMMIT_SHA -x "git commit --amend --author 'NEW_CHANGE' --no-edit" – Lawana

I recommend to add --rebase-merges (short -r) option, to keep the topology of your branch intact if it contains some merges. – Stichter

@ChrisMaes: Please note that git commit --amend --author ... does not change the committer, only the author! So while it may appear that your email was changed, there is, in fact, metadata in the repository that says who the old committer is. While the filter-branch (or filter-repo) methods are more crude, they actually change both. Proof: curl -s https://api.github.com/repos/sshine/author-committer/commits | jq '.[0].commit | { author, committer }' -- I did a git commit --amend --author="John Doe ..." here, and you can see that the committer is not John Doe. – Twin

As a note, you can use --root in place of HEAD if trying to specify every commit of the rreo. – Bowel

@ChrisMaes @Twin to change also the committer information of the 4 latest commits, you can use git rebase -i HEAD~4 -x \ "GIT_COMMITTER_NAME='Author Name' GIT_COMMITTER_EMAIL='Author Name <[email protected]>' git commit --amend --author 'Author Name <[email protected]>' --no-edit" – Swarth

@Swarth I have added this in my answer. Thanks for the proposal, which I have tweaked a little. – Staub

Answer 4

The highest voted answer here is now out of date. Git shows this scary warning when using git filter-branch -

WARNING: git-filter-branch has a glut of gotchas generating mangled history
         rewrites. Hit Ctrl-C before proceeding to abort, then use an
         alternative filtering tool such as 'git filter-repo'
         (https://github.com/newren/git-filter-repo/) instead.

filter-repo is not (yet) part of git and needs to be installed separately.

# Requires git v2.22+ and python v3.5+. Check with -
git --version && python3 --version
    
# Install using pip
pip3 install git-filter-repo    
    

To replace only the email in previous commits run the the command like this -

git filter-repo --email-callback '
    return email if email != b"incorrect@email" else b"correct@email"
' 

To replace both, email and author name in the previous commits run the the command like this -

git filter-repo --commit-callback '
    if commit.author_email == b"incorrect@email":
        commit.author_email = b"correct@email" 
        commit.author_name = b"Correct Name"
        commit.committer_email = b"correct@email" 
        commit.committer_name = b"Correct Name"
' 

Make sure the indents are there when you paste the command in your terminal. The callback uses python syntax so indents are important.

Read more about filter-repo callbacks in the docs.

Mohr

Thank you. It worked! If you're getting zsh: command not found: pip on a Mac, try pip3 - pip3 install git-filter-repo. – Kantor

on Windows (in ConEmu terminal), in a venv, I had to swap quotes and make it a one-liner, and add --force (because I made commits since last pushing): git filter-repo --force --email-callback " return email if email != b'wrong@email' else b'correct@email'" – Lille

Since the question asked about amending several commits, it's worth noting that filter-repo works on the complete repository by default, and you can specify --refs=branchname or a range of commits like --refs=HEAD^^..HEAD to override. – Olivier

Answer 5

This method was documented by GitHub for this very purpose (though GitHub has since removed it). The steps are:

1. Open the terminal and make a bare clone of your repo

git clone --bare https://github.com/user/repo.git
cd repo

2. Edit the following script (replacing OLD_EMAIL, CORRECT_EMAIL, and CORRECT_NAME)

#!/bin/sh

git filter-branch --env-filter '
OLD_EMAIL="[email protected]"
CORRECT_NAME="Your Correct Name"
CORRECT_EMAIL="[email protected]"
if [ "$GIT_COMMITTER_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_COMMITTER_NAME="$CORRECT_NAME"
    export GIT_COMMITTER_EMAIL="$CORRECT_EMAIL"
fi
if [ "$GIT_AUTHOR_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_AUTHOR_NAME="$CORRECT_NAME"
    export GIT_AUTHOR_EMAIL="$CORRECT_EMAIL"
fi
' --tag-name-filter cat -- --branches --tags

3. Copy/paste the script into your terminal and press enter to run it.
4. Push your changes with git push --force --tags origin 'refs/heads/*' and you're done!

Baiel

I followed the same instructions on GitHub that you referenced, and GitHub looks right now. However, I'm a Git newb and not sure how to sync my local repo back up after that. When I pull I get the same "refusing to merge unrelated histories" error mentioned in another answer. I think I need to rebase against that new commit history, but I'd very much appreciate more specific steps. – Melendez

@Melendez if you are happy with the repo as it is on github, you can delete (or perhaps move to another location) the folder you have locally and simply clone from github – Baiel

Thanks, I know, but that doesn't seem like the idiomatic GitHub/Git way. – Melendez

Answer 6

I believe what you are looking for is git rebase --interactive

It allows you to go reset to an specific commit and then go throw the history changing adding or grouping commits

Here you have an explanation https://web.archive.org/web/20100213104931/http://blog.madism.org/index.php/2007/09/09/138-git-awsome-ness-git-rebase-interactive

Fusspot

Answer 7

If you're looking for a script, this one came handy for me.

1. Download the script from GitHub and save it to an easily-accessible location.

2. Change the permissions of the script file to allow it to execute:

   chmod +x changeauthor.sh

3. Navigate into the repository with the incorrect commit history

   cd path/to/repo

4. Run the script (with or without flags)

   ../path/to/changeauthor.sh --old-email [email protected] \
       --new-email [email protected] --new-name "Kaka Ruto" --remote origin
   

Be careful as this will rewrite all history in your current dir repository! Good thing is the script give you warnings and info about what you're about to do

Read more here https://www.adamdehaven.com/blog/update-commit-history-author-information-for-git-repository/

Curr

Answer 8

As suggested in this answer git-filter-repo is preferred for the task.

However to simply change author name and/or email one can use --mailmap or --use-mailmap instead of callbacks.

You need to create a mailmap file according to the format (see git-filter-repo/docs or git-scm.com/docs)

Then simply run

git filter-repo --mailmap .mailmap

Ideatum