GitHub

Using different SSH keys and Email per GitHub Organisation #

This guide shows how to make to make git automatically use an SSH key and email, but only for a specific client. This works anywhere on your machine, without environment variables, direnv, or using alias.

You’ll need this for clients that require developers to use a project-specific Github account, for instance when they have their own GitHub Enterprise account, or require the use of their own accounts and SSO. We’ll use this client, and the corresponding example-org Github organization as an example.

First, open your global git config file (.gitconfig at the root of your Home directory on MacOS) and add the following:

[includeIf "hasconfig:remote.*.url:git@github.com:example-org/**"]
    path = /Users/<your-username>/dev/example-org/.gitconfig

Now when interacting with the example-org Github organisation it will use the example-org/.gitconfig file. You can place this custom Git config file anywhere you want.

Second, open that file and specify 2 parameters:

[user]
    email = example@example.com
[core]
    sshCommand = "ssh -i /path/to/ssh/key -o IdentitiesOnly=yes"

core.sshCommand will override the ssh command used by git with one that specifies a client specific SSH key. Be sure to swap out both the email and the path to the SSH key you want to use. The email is optional, and you can add other git config parameters here too.

Note: Check your .ssh/config file. There might be an override in IdentityFile under Host *. Comment this out, or make it more specific.