Manage GitHub, and Gitlab accounts on single machine with SSH keys on Mac

For this example, I will use the same email to produce two different SSH keys: 1 for Github, and 1 for Gitlab. The logic also extends to different emails, and multiple Github, and Gitlab accounts.

Step 1. Generate new SSH keys

Check if you have any existing SSH keysls -al ~/.ssh on your machine. You can reuse the existing key pair if it is available, but I suggest that you don’t.

To create private and public SSH pairs for your personal, and work accounts, run:

ssh-keygen -t rsa -C "personal@mail.com" -f ~/.ssh/id_rsa_gitlab
ssh-keygen -t rsa -C "personal@mail.com" -f ~/.ssh/id_rsa_github

These will produce four different files namely:

~/.ssh/id_rsa_github
~/.ssh/id_rsa_github.pub
~/.ssh/id_rsa_gitlab
~/.ssh/id_rsa_gitlab.pub

Step 2. Add SSH keys to Github, and Gitlab

Github
Copy corresponding public key of your Gitlab account
pbcopy < ~/.ssh/id_rsa_github.pub

Logon to your Github account. Then go to
Settings > SSH and GPG Keys > New SSH key

Paste the public key on the Key, and edit the Title part as you please.

Adding SSH keys on GitHub

Gitlab
Copy corresponding public key of your Gitlab account
pbcopy < ~/.ssh/id_rsa_gitlab.pub

Logon to your Gitlab account. Then go to Settings > SSH Keys

Paste the public key on the Key, and edit the Title part as you please.

Adding SSH keys on GitLab

Step 3: Register SSH Keys with the ssh-agent

Register all SSH keys on your local machine using the ssh-agent

ssh-add ~/.ssh/id_rsa_github
ssh-add ~/.ssh/id_rsa_gitlab

Step 4: Editing Config File

Create a configuration file that will add the different SSH keys for all online repositories and emails that we created earlier

touch ~/.ssh/config    // Creates config file if it does not exist
vi ~/.ssh/config .     // Edit config file

The config file should look like this

# This is a comment
# Personal github account
Host github.com
   HostName github.com
   User git
   IdentityFile ~/.ssh/id_rsa_github
# Personal gitlab account
Host gitlab.com
   HostName gitlab.com
   User bgit
   IdentityFile ~/.ssh/id_rsa_gitlab

After following the above steps, you should be able clone, and edit both your GitHub, and GitLab repositories on your local machine. Thanks!