git and GitHub username are different things

Code for this post can be found in the config-username branch of the git-examples repository.

Your username on GitHub does not have to match your git username. Let’s say I change my name to “a” and commit a file called whoami. This file is pushed to GitHub.

git config --global user.name "a";
echo a >> whoami;
git commit -m "whoami a"
git push;

I can see my name has changed:

git config user.name

Now let’s change my name to “b”:

git config --global user.name "b"
echo b >> whoami;
git commit -m "whoami b"
git push;

With the following command I can see which users were responsible for each commit (git log formatting is quite powerful by the way).

git log --pretty="format:%s - %an" -2

Which gives:

whoami b - b
whoami a - a

The first column is the commit message (the %s subject part), the part after the dash is the author of the commit (%an). As you can see the commits are linked to 2 different authors because we changed our name locally inbetween commits. On GitHub however you won’t see this because there only the GitHub username is displayed: