Nicolas Neudeck

Manage Multiple SSH Key for GitHub on One Machine ​

March 23, 2024

GitHub allows developers to collaborate in teams on projects and maintain version control over our code. Like many others, I work at a company, but also develop my own projects on the side. This means I have a personal GitHub account, a GitHub account from the company, and recently, a third account from a client where I also contribute to the repository. Managing multiple SSH keys on one machine has always been a bit cumbersome, but in this tutorial, I'll explain how I seamlessly switch from one GitHub account to the next and be able to commit and push in different repositories.

Solution ​

The solution is to define host aliases in the SSH config file (each alias for an account) and have seperate directories for each github account.

This is how:

  1. Generate SSH key pairs for accounts and add them to GitHub accounts.
  2. Edit/Create SSH config file (~/.ssh/config):
bash
# Default GitHub account: personal
Host github.com
    HostName github.com
    IdentityFile ~/.ssh/id_personal
    IdentitiesOnly yes

# Work GitHub account: work
Host github-work
    HostName github.com
    IdentityFile ~/.ssh/id_work
    IdentitiesOnly yes

NOTE: If you use any account frequently, you should use the default hostname (github.com).

  1. Add SSH private keys to your agent:
bash
ssh-add ~/.ssh/id_personal
ssh-add ~/.ssh/id_work

Test your connection: ​

bash
ssh-keyscan github.com >> ~/.ssh/known_hosts
ssh -T git@github.com
ssh -T git@github-work

If everything is OK, you will see these messages:

plaintext
Hi personal! You've successfully authenticated, but GitHub does not provide shell access.

Hi work! You've successfully authenticated, but GitHub does not provide shell access.

Now all are set, you need to remember:

bash
git@github-work:org/project.git > user is work
git@github.com:org/project.git  > user is personal

If you need to clone a repository, just do:

bash
git clone git@github-work:org1/project1.git /path/to/project1
cd /path/to/project1
git config user.email "email@example.com"
git config user.name  "FirstName LastName"

Migrate repository ​

If you already have the repo set up, after the SSH config instructions, you need to change the URL of origin, just do:

bash
cd /path/to/project2
git remote set-url origin git@github-work:org2/project2.git
git config user.email "email@example.com"
git config user.name  "FirstName LastName"

Set up Git Configuration ​

to avoid the constant need to manually configure your git email and name like this:

bash
git config user.email "email@example.com"
git config user.name  "FirstName LastName"

You can create mutilple Git Config files:

  1. Edit your ~/.gitconfig file
bash
[user]
  email = email@personal.com
  name = FirstName LastName
[includeIf "gitdir:~/work_repositories/"]
    path = ~/work_repositories/.gitconfig
  1. Create and edit a second Git Config file for your work account (~/work_repositories/.gitconfig):
bash
[user]
  email = email@work.com
  name = FirstName LastName

Everytime you are in the ~/work_repositories/ directory, your work email will be used when you commit and push code.

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