NOTE: This answer changes SHA1s, so take care when using it on a branch that has already been pushed. If you only want to fix the spelling of a name or update an old email, Git lets you do this without rewriting history using .mailmap. See my other answer.

Using Rebase

First, if you haven’t already done so, you will likely want to fix your name in git-config:

git config --global user.name "New Author Name"
git config --global user.email "<[email protected]>"

This is optional, but it will also make sure to reset the committer name, too, assuming that’s what you need.

To rewrite metadata for a range of commits using a rebase, do

git rebase -r <some commit before all of your bad commits> 
    --exec 'git commit --amend --no-edit --reset-author'

--exec will run the git commit step after each commit is rewritten (as if you ran git commit && git rebase --continue repeatedly).

If you also want to change your first commit (also called the ‘root’ commit), you will have to add --root to the rebase call.

This will change both the committer and the author to your user.name/user.email configuration. If you did not want to change that config, you can use --author "New Author Name <[email protected]>" instead of --reset-author. Note that doing so will not update the committer — just the author.

Single Commit

If you just want to change the most recent commit, a rebase is not necessary. Just amend the commit:

git commit --amend --no-edit --reset-author

Entire project history

git rebase -r --root --exec "git commit --amend --no-edit --reset-author"

For older Git clients (pre-July 2020)

-r,--rebase-merges may not exist for you. As a replacement, you can use -p. Note that -p has serious issues and is now deprecated.

This answer uses git-filter-branch, for which the docs now give this warning:

git filter-branch has a plethora of pitfalls that can produce non-obvious manglings of the intended history rewrite (and can leave you with little time to investigate such problems since it has such abysmal performance). These safety and performance issues cannot be backward compatibly fixed and as such, its use is not recommended. Please use an alternative history filtering tool such as git filter-repo. If you still need to use git filter-branch, please carefully read SAFETY (and PERFORMANCE) to learn about the land mines of filter-branch, and then vigilantly avoid as many of the hazards listed there as reasonably possible.

Changing the author (or committer) would require rewriting all of the history. If you’re okay with that and think it’s worth it then you should check out git filter-branch. The manual page includes several examples to get you started. Also note that you can use environment variables to change the name of the author, committer, dates, etc. — see the “Environment Variables” section of the git manual page.

Specifically, you can fix all the wrong author names and emails for all branches and tags with this command (source: GitHub help):

#!/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

For using alternative history filtering tool git filter-repo, you can first install it and construct a git-mailmap according to the format of gitmailmap.

Proper Name <[email protected]> Commit Name <[email protected]>

And then run filter-repo with the created mailmap:

git filter-repo --mailmap git-mailmap

One liner, but be careful if you have a multi-user repository – this will change all commits to have the same (new) author and committer.

git filter-branch -f --env-filter "GIT_AUTHOR_NAME='Newname'; GIT_AUTHOR_EMAIL='new@email'; GIT_COMMITTER_NAME='Newname'; GIT_COMMITTER_EMAIL='new@email';" HEAD

With linebreaks in the string (which is possible in bash):

git filter-branch -f --env-filter "
    GIT_AUTHOR_NAME='Newname'
    GIT_AUTHOR_EMAIL='new@email'
    GIT_COMMITTER_NAME='Newname'
    GIT_COMMITTER_EMAIL='new@email'
  " HEAD

You can also do:

git filter-branch --commit-filter '
        if [ "$GIT_COMMITTER_NAME" = "<Old Name>" ];
        then
                GIT_COMMITTER_NAME="<New Name>";
                GIT_AUTHOR_NAME="<New Name>";
                GIT_COMMITTER_EMAIL="<New Email>";
                GIT_AUTHOR_EMAIL="<New Email>";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD

Note, if you are using this command in the Windows command prompt, then you need to use " instead of ':

git filter-branch --commit-filter "
        if [ "$GIT_COMMITTER_NAME" = "<Old Name>" ];
        then
                GIT_COMMITTER_NAME="<New Name>";
                GIT_AUTHOR_NAME="<New Name>";
                GIT_COMMITTER_EMAIL="<New Email>";
                GIT_AUTHOR_EMAIL="<New Email>";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi" HEAD

It happens when you do not have a $HOME/.gitconfig initialized. You may fix this as:

git config --global user.name "you name"
git config --global user.email [email protected]
git commit --amend --reset-author

Tested with Git version 1.7.5.4.

Note that this fixes only the last commit.

In the case where just the top few commits have bad authors, you can do this all inside git rebase -i using the exec command and the --amend commit, as follows:

git rebase -i HEAD~6 # as required

which presents you with the editable list of commits:

pick abcd Someone else's commit
pick defg my bad commit 1
pick 1234 my bad commit 2

Then add exec ... --author="..." lines after all lines with bad authors:

pick abcd Someone else's commit
pick defg my bad commit 1
exec git commit --amend --author="New Author Name <[email protected]>" -C HEAD
pick 1234 my bad commit 2
exec git commit --amend --author="New Author Name <[email protected]>" -C HEAD

save and exit editor (to run).

This solution may be longer to type than some others, but it’s highly controllable – I know exactly what commits it hits.

Thanks to @asmeurer for the inspiration.

For a single commit:

git commit --amend --author="Author Name <[email protected]>"

(extracted from asmeurer’s answer)

GitHub originally had a nice solution (broken link), which was the following shell script:

#!/bin/sh

git filter-branch --env-filter '

an="$GIT_AUTHOR_NAME"
am="$GIT_AUTHOR_EMAIL"
cn="$GIT_COMMITTER_NAME"
cm="$GIT_COMMITTER_EMAIL"

if [ "$GIT_COMMITTER_EMAIL" = "[email protected]" ]
then
    cn="Your New Committer Name"
    cm="Your New Committer Email"
fi
if [ "$GIT_AUTHOR_EMAIL" = "[email protected]" ]
then
    an="Your New Author Name"
    am="Your New Author Email"
fi

export GIT_AUTHOR_NAME="$an"
export GIT_AUTHOR_EMAIL="$am"
export GIT_COMMITTER_NAME="$cn"
export GIT_COMMITTER_EMAIL="$cm"
'

A single command to change the author for the last N commits:

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

NOTES

• replace HEAD~N with the reference until where you want to rewrite your commits. This can be a hash, HEAD~4, a branch name, …
• 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
exec git commit --amend --author 'Author Name <[email protected]>' --no-edit
pick abb60f9 add new feature
exec git commit --amend --author 'Author Name <[email protected]>' --no-edit
pick dc18f70 bugfix
exec git commit --amend --author 'Author Name <[email protected]>' --no-edit

You can then still modify some lines to see where you want to change the author. This gives you a nice middle ground between automation and control: you see the steps that will run, and once you save everything will be applied at once.

Note that if you already fixed the author information with git config user.name <your_name> and git config user.email <your_email>, you can also use this command:

git rebase -i HEAD~N -x "git commit --amend --reset-author --no-edit"

As docgnome mentioned, rewriting history is dangerous and will break other people’s repositories.

But if you really want to do that and you are in a bash environment (no problem in Linux, on Windows, you can use git bash, that is provided with the installation of git), use git filter-branch:

git filter-branch --env-filter '
  if [ $GIT_AUTHOR_EMAIL = bad@email ];
    then GIT_AUTHOR_EMAIL=correct@email;
  fi;
export GIT_AUTHOR_EMAIL'

To speed things up, you can specify a range of revisions you want to rewrite:

git filter-branch --env-filter '
  if [ $GIT_AUTHOR_EMAIL = bad@email ];
    then GIT_AUTHOR_EMAIL=correct@email;
  fi;
export GIT_AUTHOR_EMAIL' HEAD~20..HEAD

I should point out that if the only problem is that the author/email is different from your usual, this is not a problem. The correct fix is to create a file called .mailmap at the base of the directory with lines like

Name you want <email you want> Name you don't want <email you don't want>

And from then on, commands like git shortlog will consider those two names to be the same (unless you specifically tell them not to). See https://schacon.github.io/git/git-shortlog.html for more information.

This has the advantage of all the other solutions here in that you don’t have to rewrite history, which can cause problems if you have an upstream, and is always a good way to accidentally lose data.

Of course, if you committed something as yourself and it should really be someone else, and you don’t mind rewriting history at this point, changing the commit author is probably a good idea for attribution purposes (in which case I direct you to my other answer here).

You can use this as a alias so you can do:

git change-commits GIT_AUTHOR_NAME "old name" "new name"

or for the last 10 commits:

git change-commits GIT_AUTHOR_EMAIL "[email protected]" "[email protected]" HEAD~10..HEAD

Add to ~/.gitconfig:

[alias]
    change-commits = "!f() { VAR=$1; OLD=$2; NEW=$3; shift 3; git filter-branch --env-filter "if [[ \"$`echo $VAR`\" = '$OLD' ]]; then export $VAR='$NEW'; fi" $@; }; f "

Source: https://github.com/brauliobo/gitconfig/blob/master/configs/.gitconfig

Hope it is useful.

A safer alternative to git’s filter-branch is filter-repo tool as suggested by git docs here.

git filter-repo --commit-callback '
  old_email = b"[email protected]"
  correct_name = b"Your Correct Name"
  correct_email = b"[email protected]"
  
  if commit.committer_email == old_email :
    commit.committer_name = correct_name
    commit.committer_email = correct_email

  if commit.author_email == old_email : 
    commit.author_name = correct_name
    commit.author_email = correct_email
  '

The above command mirrors the logic used in this script but uses filter-repo instead of filter-branch.

The code body after commit-callback option is basically python code used for processing commits. You can write your own logic in python here. See more about commit object and its attributes here.

Since filter-repo tool is not bundled with git you need to install it separately.

See Prerequisties and Installation Guide

If you have a python env >= 3.5, you can use pip to install it.

pip3 install git-filter-repo

Note: It is strongly recommended to try filter-repo tool on a fresh clone. Also remotes are removed once the operation is done. Read more on why remotes are removed here. Also read the limitations of this tool under INTERNALS section.

This is a more elaborated version of @Brian’s version:

To change the author and committer, you can do this (with linebreaks in the string which is possible in bash):

git filter-branch --env-filter '
    if [ "$GIT_COMMITTER_NAME" = "<Old name>" ];
    then
        GIT_COMMITTER_NAME="<New name>";
        GIT_COMMITTER_EMAIL="<New email>";
        GIT_AUTHOR_NAME="<New name>";
        GIT_AUTHOR_EMAIL="<New email>";
    fi' -- --all

You might get one of these errors:

1. The temporary directory exists already
2. Refs starting with refs/original exists already
   (this means another filter-branch has been run previously on the repository and the then original branch reference is backed up at refs/original)

If you want to force the run in spite of these errors, add the --force flag:

git filter-branch --force --env-filter '
    if [ "$GIT_COMMITTER_NAME" = "<Old name>" ];
    then
        GIT_COMMITTER_NAME="<New name>";
        GIT_COMMITTER_EMAIL="<New email>";
        GIT_AUTHOR_NAME="<New name>";
        GIT_AUTHOR_EMAIL="<New email>";
    fi' -- --all

A little explanation of the -- --all option might be needed: It makes the filter-branch work on all revisions on all refs (which includes all branches). This means, for example, that tags are also rewritten and is visible on the rewritten branches.

A common “mistake” is to use HEAD instead, which means filtering all revisions on just the current branch. And then no tags (or other refs) would exist in the rewritten branch.

When taking over an unmerged commit from another author, there is an easy way to handle this.

git commit --amend --reset-author

1. run git rebase -i <sha1 or ref of starting point>

2. mark all commits that you want to change with edit (or e)

3. loop the following two commands until you have processed all the commits:

   git commit --amend --reuse-message=HEAD --author="New Author <[email protected]>"
   ;
   git rebase --continue

This will keep all the other commit information (including the dates).
The --reuse-message=HEAD option prevents the message editor from launching.

I use the following to rewrite the author for an entire repository, including tags and all branches:

git filter-branch --tag-name-filter cat --env-filter "
  export GIT_AUTHOR_NAME='New name';
  export GIT_AUTHOR_EMAIL='New email'
" -- --all

Then, as described in the MAN page of filter-branch, remove all original refs backed up by filter-branch (this is destructive, backup first):

git for-each-ref --format="%(refname)" refs/original/ | 
xargs -n 1 git update-ref -d

I adapted this solution which works by ingesting a simple author-conv-file (format is the same as one for git-cvsimport). It works by changing all users as defined in the author-conv-file across all branches.

We used this in conjunction with cvs2git to migrate our repository from cvs to git.

i.e. Sample author-conv-file

john=John Doe <[email protected]>
jill=Jill Doe <[email protected]>

The script:

 #!/bin/bash

 export $authors_file=author-conv-file

 git filter-branch -f --env-filter '

 get_name () {
     grep "^$1=" "$authors_file" |
     sed "s/^.*=(.*) <.*>$/1/"
 }

 get_email () {
     grep "^$1=" "$authors_file" |
     sed "s/^.*=.* <(.*)>$/1/"
 }

 GIT_AUTHOR_NAME=$(get_name $GIT_COMMITTER_NAME) &&
     GIT_AUTHOR_EMAIL=$(get_email $GIT_COMMITTER_NAME) &&
     GIT_COMMITTER_NAME=$GIT_AUTHOR_NAME &&
     GIT_COMMITTER_EMAIL=$GIT_AUTHOR_EMAIL &&
     export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL &&
     export GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL
 ' -- --all

I found the presented versions way to aggressive, especially if you commit patches from other developers, this will essentially steal their code.

The version below does work on all branches and changes the author and comitter separately to prevent that.

Kudos to leif81 for the all option.

#!/bin/bash

git filter-branch --env-filter '
if [ "$GIT_AUTHOR_NAME" = "<old author>" ];
then
    GIT_AUTHOR_NAME="<new author>";
    GIT_AUTHOR_EMAIL="<[email protected]>";
fi
if [ "$GIT_COMMITTER_NAME" = "<old committer>" ];
then
    GIT_COMMITTER_NAME="<new commiter>";
    GIT_COMMITTER_EMAIL="<[email protected]>";
fi
' -- --all

1. Change commit author name & email by Amend, then replacing old-commit with new-one:

   $ git checkout <commit-hash>                            # checkout to the commit need to modify  
   $ git commit --amend --author "name <[email protected]>" # change the author name and email
   
   $ git replace <old-commit-hash> <new-commit-hash>      # replace the old commit by new one
   $ git filter-branch -- --all                           # rewrite all futures commits based on the replacement                   
   
   $ git replace -d <old-commit-hash>     # remove the replacement for cleanliness 
   $ git push -f origin HEAD              # force push 
   

2. Another way Rebasing:

   $ git rebase -i <good-commit-hash>      # back to last good commit
   
   # Editor would open, replace 'pick' with 'edit' before the commit want to change author
   
   $ git commit --amend --author="author name <[email protected]>"  # change the author name & email
   
   # Save changes and exit the editor
   
   $ git rebase --continue                # finish the rebase
   

The fastest, easiest way to do this is to use the –exec argument of git rebase:

git rebase -i -p --exec 'git commit --amend --reset-author --no-edit'

This will create a todo-list that looks like this:

pick ef11092 Blah blah blah
exec git commit --amend --reset-author --no-edit
pick 52d6391 Blah bloh bloo
exec git commit --amend --reset-author --no-edit
pick 30ebbfe Blah bluh bleh
exec git commit --amend --reset-author --no-edit
...

and this will work all automatically, which works when you have hundreds of commits.

One-liner with filter-repo:

You can use the callbacks feature of git-filter-repo (a recommended replacement for filter-branch) to change the name and email associated with all the commits:

git filter-repo --name-callback 'return b"New Name"' --email-callback 'return b"[email protected]"'

This is more performant and potentially more reliable than solutions using filter-branch.

Note that the above command changes the authors (and committer) of all commits, if you want to effectively “edit” a certain author, and only modify the commits of that specific author, then use the --commit-callback option like this:

git filter-repo --commit-callback '
old_email = b"[email protected]"
new_email = b"[email protected]"
new_name = b"New Author"

if commit.author_email == old_email:
    commit.author_email = new_email
    commit.author_name = new_name

if commit.committer_email == old_email:
    commit.committer_email = new_email
    commit.committer_name = new_name
'

(Just change the old_email, new_email, and new_name variables in the command above to the right values.)

If you are the only user of this repository, you can rewrite history using either git filter-branch (as svick wrote), or git fast-export/git fast-import plus filter script (as described in article referenced in docgnome answer), or interactive rebase. But either of those would change revisions from first changed commit onwards; this means trouble for anybody that based his/her changes on your branch pre-rewrite.

RECOVERY

If other developers didn’t based their work on pre-rewrite version, simplest solution would be to re-clone (clone again).

Alternatively they can try git rebase --pull, which would fast-forward if there weren’t any changes in their repository, or rebase their branch on top of re-written commits (we want to avoid merge, as it would keep pre-rewrite comits forever). All of this assuming that they do not have not comitted work; use git stash to stash away changes otherwise.

If other developers use feature branches, and/or git pull --rebase doesn’t work e.g. because upstream is not set up, they have to rebase their work on top of post-rewrite commits. For example just after fetching new changes (git fetch), for a master branch based on / forked from origin/master, one needs to run

$ git rebase --onto origin/master origin/master@{1} master

Here origin/master@{1} is pre-rewrite state (before fetch), see gitrevisions.

Alternate solution would be to use refs/replace/ mechanism, available in Git since version 1.6.5. In this solution you provide replacements for commits that have wrong email; then anybody who fetches ‘replace’ refs (something like fetch = +refs/replace/*:refs/replace/* refspec in appropriate place in their .git/config) would get replacements transparently, and those who do not fetch those refs would see old commits.

The procedure goes something like this:

1. Find all commits with wrong email, for example using

   $ git log [email protected] --all
   

2. For each wrong commit, create a replacement commit, and add it to object database

   $ git cat-file -p <ID of wrong commit> | 
     sed -e 's/user@wrong.email/[email protected]/g' > tmp.txt
   $ git hash-object -t commit -w tmp.txt
   <ID of corrected commit>
   

3. Now that you have corrected commit in object database, you have to tell git to automatically and transparently replace wrong commit by corrected one using git replace command:

   $ git replace <ID of wrong commit> <ID of corrected commit>
   

4. Finally, list all replacement to check if this procedure succeded

   $ git replace -l
   

   and check if replacements take place

   $ git log [email protected] --all
   

You can of course automate this procedure… well, all except using git replace which doesn’t have (yet) batch mode, so you would have to use shell loop for that, or replace “by hand”.

NOT TESTED! YMMV.

^{Note that you might encounter some rough corners when using refs/replace/ mechanism: it is new, and not yet very well tested}.

Note that git stores two different e-mail addresses, one for the committer (the person who committed the change) and another one for the author (the person who wrote the change).

The committer information isn’t displayed in most places, but you can see it with git log -1 --format=%cn,%ce (or use show instead of log to specify a particular commit).

While changing the author of your last commit is as simple as git commit --amend --author "Author Name <[email protected]>", there is no one-liner or argument to do the same to the committer information.

The solution is to (temporarily, or not) change your user information, then amend the commit, which will update the committer to your current information:

git config user.email [email protected] 
git commit --amend

For reset ALL commits (including first commit) to current user and current timestamp:

git rebase --root --exec "git commit --amend --no-edit --date 'now' --reset-author"

If the commits you want to fix are the latest ones, and just a couple of them, you can use a combination of git reset and git stash to go back an commit them again after configuring the right name and email.

The sequence will be something like this (for 2 wrong commits, no pending changes):

git config user.name <good name>
git config user.email <good email>
git reset HEAD^
git stash
git reset HEAD^
git commit -a
git stash pop
git commit -a

If you are using Eclipse with EGit, then there is a quite easy solution.
Assumption: you have commits in a local branch ‘local_master_user_x’ which cannot be pushed to a remote branch ‘master’ because of the invalid user.

1. Checkout the remote branch ‘master’
2. Select the projects/folders/files for which ‘local_master_user_x’ contains changes
3. Right-click – Replace with – Branch – ‘local_master_user_x’
4. Commit these changes again, this time as the correct user and into the local branch ‘master’
5. Push to remote ‘master’

Using interactive rebase, you can place an amend command after each commit you want to alter. For instance:

pick a07cb86 Project tile template with full details and styling
x git commit --amend --reset-author -Chead

We have experienced an issue today where a UTF8 character in an author name was causing trouble on the build server, so we had to rewrite the history to correct this. The steps taken were:

Step 1: Change your username in git for all future commits, as per instructions here:
https://help.github.com/articles/setting-your-username-in-git/

Step 2: Run the following bash script:

#!/bin/sh

REPO_URL=ssh://path/to/your.git
REPO_DIR=rewrite.tmp

# Clone the repository
git clone ${REPO_URL} ${REPO_DIR}

# Change to the cloned repository
cd ${REPO_DIR}

# Checkout all the remote branches as local tracking branches
git branch --list -r origin/* | cut -c10- | xargs -n1 git checkout

# Rewrite the history, use a system that will preseve the eol (or lack of in commit messages) - preferably Linux not OSX
git filter-branch --env-filter '
OLD_EMAIL="[email protected]"
CORRECT_NAME="New Me"

if [ "$GIT_COMMITTER_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_COMMITTER_NAME="$CORRECT_NAME"
fi
if [ "$GIT_AUTHOR_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_AUTHOR_NAME="$CORRECT_NAME"
fi
' --tag-name-filter cat -- --branches --tags

# Force push the rewritten branches + tags to the remote
git push -f

# Remove all knowledge that we did something
rm -rf ${REPO_DIR}

# Tell your colleagues to `git pull --rebase` on all their local remote tracking branches

Quick overview: Checkout your repository to a temp file, checkout all the remote branches, run the script which will rewrite the history, do a force push of the new state, and tell all your colleagues to do a rebase pull to get the changes.

We had trouble with running this on OS X because it somehow messed up line endings in commit messages, so we had to re-run it on a Linux machine afterwards.

Your problem is really common. See “Using Mailmap to Fix Authors List in Git”

For the sake of simplicity, I have created a script to ease the process: git-changemail

After putting that script on your path, you can issue commands like:

• Change author matchings on current branch

  $ git changemail -a [email protected] -n newname -m [email protected]
  

• Change author and committer matchings on <branch> and <branch2>. Pass -f to filter-branch to allow rewriting backups

  $ git changemail -b [email protected] -n newname -m [email protected] -- -f <branch> <branch2>
  

• Show existing users on repo

  $ git changemail --show-both
  

By the way, after making your changes, clean the backup from the filter-branch with: git-backup-clean