So I needed a way to change the author’s name and email on the commits, after searching a little using google I encountered this page on GitHub, however I’ve decided to write a tutorial on it anyways, we’ll use the code from GitHub though.

Ok to do this we are going to use a bash script (which is basically a  list of commands to execute) they’re work on linux and also on windows if you have msysgit. here’s the code.

git filter-branch --env-filter '

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

if [ "$GIT_COMMITTER_EMAIL" = "EMAIL_OF_COMMITER_HERE" ]
then
    cn="NEW_NAME_COMMITER"
    cm="NEW_EMAIL_COMMITER"
fi
if [ "$GIT_AUTHOR_EMAIL" = "EMAIL_OF_AUTHOR_HERE" ]
then
    an="NEW_NAME_AUTHOR"
    am="NEW_EMAIL_AUTHOR"
fi

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

As you can see this code uses the git filter-branch command, and everything on line 2-22 is basically the filter code. Now to replace a certain commiter or author just replace EMAIL_OF_AUTHOR/COMMITER_HERE with the email of that committer/author, and replace NEW_NAME_COMMITER/AUTHOR and NEW_EMAIL_COMMITER/AUTHOR with the new email and name you want him/her to have. You can replace multiple commiters/authors by copy-pasting the if blocks (See below for that part)

if [ "$GIT_COMMITTER_EMAIL" = "EMAIL_OF_COMMITER_HERE" ]
then
    cn="NEW_NAME_COMMITER"
    cm="NEW_EMAIL_COMMITER"
fi
if [ "$GIT_AUTHOR_EMAIL" = "EMAIL_OF_AUTHOR_HERE" ]
then
    an="NEW_NAME_AUTHOR"
    am="NEW_EMAIL_AUTHOR"
fi

You can duplicate these for as many authors/commiters you want to replace. now after you finished this document save it somewhere you can access it easily (From the command line/console), and after that go inside your git repository’s folder (Ofcourse also on the command line aka console), when in there type the following.

sh /path/to/previous/saved/script.ext

When you’ve done that a progress counter will start to run, this is the git filter-branch scanning through all your commits. After this process finishes your repo will be updated with the new name/email (use “git log” to check), now to push it to a remote repository push like normal but instead of “git push” use “git push -f”, after this is done your remote repo is also updated.

Well that’s it, hope it was useful and if you have any questions or remarks don’t hesitate to post a comment

Regards, Xeross