Add a GitLab SSH key on a machine

Step 1: Check for existing SSH keys

Check if you already have an SSH key:

ls -al ~/.ssh

Look for files like id_rsa, id_ed25519, or id_ecdsa.

Step 2: Generate a new SSH key (if needed)

If you don’t have an SSH key, generate one:

ssh-keygen -t ed25519 -C "[email protected]"

Or if your system doesn’t support Ed25519:

ssh-keygen -t rsa -b 4096 -C "[email protected]"

Press Enter to accept the default file location (~/.ssh/id_ed25519 or ~/.ssh/id_rsa), and optionally set a passphrase.

Step 3: Copy your public key

Display and copy your public key:

cat ~/.ssh/id_ed25519.pub

Or if you used RSA:

cat ~/.ssh/id_rsa.pub

Copy the entire output (starts with ssh-ed25519 or ssh-rsa).

Step 4: Add the key to GitLab

1. Go to GitLab → Profile → SSH Keys (or https://gitlab.com/-/profile/keys)
2. Paste your public key into the “Key” field
3. Give it a title (e.g., “My Linux Machine”)
4. Click “Add key”

Step 5: Test the connection

Test the connection to GitLab:

ssh -T [email protected]

You should see a welcome message like: Welcome to GitLab, @username!

Optional: Start SSH agent (if needed)

If you’re using a passphrase and want to avoid typing it every time:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

(Or ~/.ssh/id_rsa if you used RSA)

Note: If you use a self-hosted GitLab instance, replace gitlab.com with your GitLab server’s hostname in step 5.