Setup multiple git identities & git user informations

/!\ Be very carrefull in your setup : any misconfiguration make all the git config to fail silently ! Go trought this guide step by step and it should be fine 😉

Setup multiple git ssh identities for git

Generate your SSH keys as per your git provider documentation.
Add each public SSH keys to your git providers acounts.

In your ~/.ssh/config, set each ssh key for each repository as in this exemple:

  Host github.com
  	HostName github.com
  	User git
  	IdentityFile ~/.ssh/github_private_key
  	IdentitiesOnly=yes
  Host gitlab.com
  	Hostname gitlab.com
  	User git
  	IdentityFile ~/.ssh/gitlab_private_key
  	IdentitiesOnly=yes

Setup dynamic git user email & name depending on folder

/!\ Require git 2.13+ for conditional include support.

The idea here is to use a different git user name & email depending on the folder you are in.

In your ~/.gitconfig, remove the [user] block and add the following (adapt this exemple to your needs) :

  [includeIf "gitdir:~/code/personal/"]
  	path = .gitconfig-personal
  [includeIf "gitdir:~/code/professional/"]
  	path = .gitconfig-professional

In your ~/.gitconfig-personal, add your personnal user informations:

  [user]
  	email = [email protected]     # note we use the noreply github mail
  	name = personal_username

In your ~/.gitconfig-professional, add your professional user informations:

  [user]
  	email = [email protected]
  	name = professional_username

Setup a GPG key

If you need to add a GPG key and bind it to a user to sign your commits, you can do so like this:

You should have GPG installed and configured like the GPG suite

Add the GPG key ID to your ~/.gitconfig-<PROFILE> config and enable commit signing:

[user]
  email = [email protected]
  name = Your NAME
  signingkey = SIGNING_KEY_ID
[commit]
  gpgsign = true

Make sure to register the right GPG binary in your ~/.gitconfig:
```
[program]
  pgp = /path/to/your/gpg2/bin
```

Test your setup

Now each repository will use the custom user info setup depending on the top-level folder.

Check your settings are taken into account, for instance in ~/code/personal/ :

$ cd ~/code/personal/
$ git config --get user.email    	# should return [email protected] as per the exemple
$ git config --get user.name     	# should return personal_username as per the exemple
$ git config --get user.signingkey	# should return the GPG key ID as configured for the user

Do the same for each folder you have setup.
You can also display and check the global git config: git config --list --global
- Or just the local config for the repository folder you are in: git config --list
Done !

Roadmap

use git config commands instead of config file manual editions (editing config directly is kind of dangerous but is more understandable, maybe keep it like this ?)