Git with Multiple E-Mail Addresses

And How I Make Sure to Commit with the Right One

Different Git Server, Different E-Mail Address

When you use Git on a daily basis, chances are that you use it with multiple remote servers—and do so with different email addresses. I personally use:

• My work email address (let’s say patrick@work.xy for the sake of brevity) for my employer’s Git server (git.work.xy to keep it short).
• My private email address (patrick@home.xy) for GitHub (github.com).
• The school’s email address (patrick@school.xy) for the Git server used for teaching (git.school.xy).

Only using each Git server on a computer dedicated for some line of work (company, private, school) is impractical for different reasons. I keep personal notes on discoveries I make when working for my job or for school, which I store in a private repository. Changing laptops just to write down that command line I already googled seven times is not practical, and just would make me to google it for the eighth time.

Furthermore, I prefer to work on my stationary PC running Arch Linux (which I use as a daily driver, by the way) for school-related work, especially when it comes to making up programming examples; I’m just less efficient working on my Windows laptop.

Two Problems, One Solution

So private, work- and school-related repositories will end up on the same computer, which requires solving two problems:

1. How shall the repositories be organized on the file system?
2. How to make sure to commit using the right email address for every repository based on its area of origin (work, school, private)?

Many developers I know just use a folder ~/projects or ~/repos, wherein they store all of their repositories. This not only causes issues when storing multiple repositories of the same name (e.g. different dotfiles or meta repositories for each area, which can be solved using prefixes like work- or school-), but also makes it harder to solve the second issue, as you’ll see shortly.

Therefore I organize my repository folders in a different way, a lot like those Git servers’s URLs are organized:

• ~/git.work.xy for my work-related repositories,
• ~/github.com for my private repositories, and
• ~/git.school.xy for my school-related repositories.

I also use a second folder level, emulating the repositories actual URLs:

• ~/git.work.xy/[customer] for the repositories of the same customer at work,
• ~/github.com/[username] for the repositories of different users and organizations, and
• ~/git.school.xy/[course] for the repositories of different courses I teach.

If you think that this messes up your home directory (following some Freedesktop standard enforced by xdg-user-dirs(1) with folders like ~/Documents and ~/Videos), feel free to add another level on top, such as ~/Repositories or ~/Projects.

This leads to deeper file system hierarchies, but makes finding repositories very easy and straightforward. It also helps solving the email address issue, which I tackle using conditional includes in my ~/.gitconfig.

Conditionally Overwriting the E-Mail Address

For every computer I use, there’s some main email address, e.g. patrick@work.xy on my employer’s laptop, or patrick@home.xy on my PC at home. For the latter case, my ~/.gitconfig starts as follows:

[user]
    name = Patrick Bucher
    email = patrick@home.xy

(I also use the signinkey option to sign my commits with the proper GPG key, but using different ones for each E-Mail address is straightforward, so I won’t list those options here.)

What I need to do for every area of work is to overwrite my email address. So I create additional Git config files in my home folder: ~/.gitconfig-work and ~/.gitconfig-school (~/.gitconfig is for private GitHub repos on this particular computer, i.e. the default shown above).

Then each config is included depending on its path from the ~/.gitconfig file:

[includeIf "gitdir:~/git.work.xy/"]
    path = ~/.gitconfig-work
[includeIf "gitdir:~/git.school.xy/"]
    path = ~/.gitconfig-school

Those files referenced then just need to overwrite the email option of the [user] section, e.g. for ~/.gitconfig-work:

[user]
    email = patrick@work.xy

Or for ~/.gitconfig-school:

[user]
    email = patrick@school.xy

Another Problem, Same Solution

Now consider that your employer also has some repositories on GitHub (github.com/employer). In this case, you can further overwrite your email using an additional conditional include in ~/.gitconfig:

[includeIf "gitdir:~/github.com/employer/"]
    path = ~/.gitconfig-work

This works as intended, as this demonstration shows:

$ cd ~/git.school.xy/cs-101/intro
$ git config user.email
patrick@school.xy

$ cd ~/git.work.xy/acme/config
$ git config user.email
patrick@work.xy

$ cd ~/github.com/patrick/dotfiles
$ git config user.email
patrick@home.xy

$ cd ~/github.com/employer/dotfiles
$ git config user.email
patrick@work.xy

I won’t do any demo commits, proving my point; the user.email setting will be used for each commit.

So you no longer have to remember running git config user.email [wh@ev.er] after cloning a repo (which you will forget) or commit with the wrong E-Mail address (which you’ll regret).