Multiple Github and SSH accounts

Hey!

Have you ever needed two different GitHub accounts — one for personal use and one for work? GitHub doesn’t allow the same SSH key to be used for multiple accounts; if you try to reuse it, you’ll see a “Key Already in Use” error.

So, what’s the best way to set this up on your computer?

First, you’ll need to create two separate SSH keys and add them to your GitHub accounts. I usually use this to generate them:

cd ~/.ssh
ssh-keygen -t ed25519 -C "your-email@company.com" -f company
ssh-keygen -t ed25519 -C "your-email@personal.com" -f personal

Now you have 4 different files at ~/.ssh. company and personal are your private keys. company.pub and personal.pub are the public keys you're going to add to Github.

Time to adjust your git config to use the proper keys in each repo. I usually have a folder workspace with all my projects, like the following structure:

.workspace
├── personal
└── company

Define your .ssh/config in the following way:

Host github-company
  HostName github.com
  AddKeysToAgent yes
  IdentityFile ~/.ssh/company

Host github.com
  HostName github.com
  AddKeysToAgent yes
  IdentityFile ~/.ssh/personal

The last step is to configure your .gitconfig:

[user]
    # Personal configuration as default
    name = Your Name
    email = your-email@personal.com

[includeIf "gitdir:~/workspace/company"]
        path = ~/.dotfiles/src/gitconfig/work

And on ~/.dotfiles/src/gitconfig/work:

[user]
    name = Your Name
    email = your-name@company.com

Now, if you want to clone a project at ~/workspace/company, you need to use the following command:

git clone git@github-company:org/repo.git

Notice the host name will be different, that's what makes the connection between git and the work's SSH key. If you try to push or pull, the SSH key will be automatically be used. Check that with git remote -v:

origin    git@github-company:org/repo.git (fetch)
origin    git@github-company:org/repo.git (push)

That's it! Feel free to comment if you have a better approach :)