Manage multiple Git accounts locally

When working on the same machine with multiple projects linked to different GitHub/GitLab/BitBucket/etc. accounts, you may need to handle multiple usernames, email addresses, and SSH keys.

Usernames and emails

A manual solution can be to set the username and email address for each repository. However if you have numerous projects, it can be tedious and error-prone.

A more systemic solution is to manage your identities in a configuration file.

Create or edit a file named .gitconfig in your Home directory.

Since Git 2.13 you can use conditional includes, which link to different config files based on the projects directories. For instance:

# Default credentials
[user]
   name = my_username
   email = me@email.com

# Work credentials
[includeIf "gitdir:~/work/"]
   path = ~/work.gitconfig

# Side projects credentials
[includeIf "gitdir:~/side-projects/"]
   path = ~/side.gitconfig

For each custom credential, create a .gitconfig file with the relevant parameters. For example, in ~/work.gitconfig:
```
[user]
    name = work_username
    email = me@corporate.com
```

Beyond username and email, you can specify any additional git parameter in these files.

SSH keys

First, generate one SSH key per Git account, and add them to their GitHub/GitLab/BitBucket accounts. You can refer to this tutorial.

Your multiple SSH keys will be handled in a file named ~/.ssh/config. Create or edit the file, and write one entry per account, like this:

# Personal GitHub
Host github.com   # Default GitHub host name
   HostName github.com
   User git
   IdentityFile ~/.ssh/id_rsa

# Work Github
Host github.com-work   # Alias host for your work GitHub account
   HostName github.com
   User git
   IdentityFile ~/.ssh/work

# Personal GitLab
Host gitlab.com   # No need for an alias if you only use one GitLab account
   HostName gitlab.com
   User git
   IdentityFile ~/.ssh/gitlab

If you have multiple accounts by the same Git provider (like GitHub in this example), you need a different Host name for each account. In the above example, we replaced Host github.com with Host github.com-work for the GitHub work account.

Finally, you will have to change the remote URL with the alias Host name in the relevant repositories. For the GitHub work account in this example:

When cloning a repository,
replace git clone git@github.com:user/repo.git
with git clone git@github.com-work:user/repo.git
For an existing repository on your machine,
update the remote address with git remote set-url origin git@github.com-work:user/repo.git,
and check the change with git remote -v.

##Usernames and emails

##SSH keys

Usernames and emails

SSH keys