Table of Contents⌗

  1. Single SSH Key Setup for GitHub
  2. Multiple Accounts per Provider
  3. SSH Configuration File Overview

Single SSH Key Setup for GitHub⌗

Step 1: Generate SSH Key⌗

First, generate a new SSH key pair:

ssh-keygen -t ed25519

When prompted, you can:

  • Press Enter to accept the default file location (~/.ssh/id_ed25519)
  • Enter a passphrase (recommended for security) or leave empty for no passphrase

Step 2: Add SSH Key to SSH Agent⌗

Add your private key to the SSH agent:

ssh-add ~/.ssh/id_ed25519

Step 3: Add Public Key to Git Provider⌗

Copy your public key:

cat ~/.ssh/id_ed25519.pub

Then copy the public key and add it to the corresponding git provider.

e.g. for GitHub:

  1. Go to GitHub.com → Settings → SSH and GPG keys
  2. Click “New SSH key”
  3. Paste your public key and give it a descriptive title
  4. Click “Add SSH key”

Step 4: Test Your Connection⌗

Verify everything works:

ssh -T git@github.com

You should see: Hi username! You've successfully authenticated...

Step 5: Configure Git (Optional)⌗

If you haven’t already, configure your Git identity:

git config --global user.name "Your Name"
git config --global user.email "your_email@example.com"

Multiple git accounts⌗

Create an SSH config file at ~/.ssh/config:

host github.com
  HostName github.com
  IdentityFile ~/.ssh/github
  User git

host gitlab.com
  HostName gitlab.com
  IdentityFile ~/.ssh/gitlab
  User git

where the IdentityFile is the path to the private key, generated earlier. The path is what you entered when prompted by ssh-keygen.

This configuration tells SSH which key to use for each service automatically.

Multiple Accounts per Provider⌗

If you have multiple accounts on the same provider (e.g., one personal and one work account on GitLab), you need:

host gitlab-private
  HostName gitlab.com
  IdentityFile ~/.ssh/gitlab_private
  User git

host gitlab-work
  HostName gitlab.com
  IdentityFile ~/.ssh/gitlab_work
  User git

Generate Separate Keys⌗

Generate different keys for each account:

ssh-keygen -t ed25519 -C "personal@example.com" -f ~/.ssh/gitlab_private
ssh-keygen -t ed25519 -C "work@example.com" -f ~/.ssh/gitlab_work

Configure Repository Remotes⌗

When setting up repositories, use the host alias in the remote URL:

git remote set-url origin git@gitlab-private:username/repo.git

The key part is git@gitlab-private: - this maps to the host gitlab-private entry in your SSH config, ensuring the correct key is used for authentication.

Key Points⌗

  • The host alias (e.g., gitlab-private) can be any name you choose
  • The format is always git@host-alias:username/repo.git
  • Each account needs its own SSH key pair
  • Add each public key to the corresponding account on the git provider