Multiple GitHub accounts on a single computer

github-multi-account.md

Step 1: Generate SSH keys for each GitHub account

1. Open a terminal on your computer.

2. Generate a new SSH key for your first GitHub account. Replace [email protected] with the email associated with your GitHub account.

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

   When prompted, save the key with a descriptive name, such as id_ed25519_first_account.

3. Repeat the process for your second GitHub account (and any additional accounts). Use a different descriptive name for each key, such as id_ed25519_second_account.

Step 2: Add the SSH keys to your SSH agent

1. Start the SSH agent in the background:

   eval "$(ssh-agent -s)"

2. Add the SSH keys to the agent. Replace path_to_key with the path to the SSH key files you generated earlier:

   ssh-add ~/.ssh/id_ed25519_first_account
   ssh-add ~/.ssh/id_ed25519_second_account

Step 3: Add SSH keys to your GitHub accounts

1. Copy the SSH key to your clipboard. Replace path_to_key with the path to the SSH key file:

   pbcopy < ~/.ssh/id_ed25519_first_account.pub

   Or, if pbcopy is not available, you can manually copy the key:

   cat ~/.ssh/id_ed25519_first_account.pub

2. Add the SSH key to your GitHub account:

   • Go to your GitHub account settings.
   • Navigate to SSH and GPG keys.
   • Click New SSH key.
   • Paste the copied key and give it a descriptive title.
   • Repeat for the second (and any additional) GitHub accounts.

Step 4: Configure SSH for multiple GitHub accounts

1. Edit the SSH configuration file (~/.ssh/config) to define configurations for each GitHub account. If the file does not exist, create it:

   nano ~/.ssh/config

2. Add configurations for each account:

   # Configuration for first GitHub account
   Host github.com-first
       HostName github.com
       User git
       IdentityFile ~/.ssh/id_ed25519_first_account
   
   # Configuration for second GitHub account
   Host github.com-second
       HostName github.com
       User git
       IdentityFile ~/.ssh/id_ed25519_second_account

Step 5: Configure Git for multiple accounts

1. Set up global Git configuration (used as a fallback):

   git config --global user.name "Your Name"
   git config --global user.email "[email protected]"

2. Set up repository-specific Git configurations. For each repository, configure Git to use the appropriate account:

   cd path/to/your/repository
   git config user.name "Your Name for First Account"
   git config user.email "[email protected]"
   git config core.sshCommand "ssh -i ~/.ssh/id_ed25519_first_account -F /dev/null"

   For repositories associated with the second account, use the corresponding SSH key:

   cd path/to/your/second-repository
   git config user.name "Your Name for Second Account"
   git config user.email "[email protected]"
   git config core.sshCommand "ssh -i ~/.ssh/id_ed25519_second_account -F /dev/null"

Step 6: Clone repositories using the correct SSH configuration

1. When cloning a repository, use the Host alias defined in your SSH configuration (~/.ssh/config). For example:

   git clone [email protected]:username/repository.git
   git clone [email protected]:username/repository.git