Git-Multi-User-with-SSH-and-Remotes

This guide walks you through setting up multiple Git identities with SSH signing and remotes. It covers generating SSH keys, configuring per-identity Git settings (including SSH commit signing), and connecting those identities to hosting services such as GitHub.

Setup

If you want Git to refuse to make commits unless you have explicitly set your identity in the repository (safer when managing multiple identities), enable:

git config --global user.useConfigOnly true

SSH Signing

To tell Git to use SSH as the commit-signing backend:

git config --global gpg.format ssh

To enable automatic commit signing by default:

git config --global commit.gpgsign true

Aliases to switch identities

On Unix-like shells (Git Bash, WSL, macOS Terminal) you may create a Git alias that sets the identity for the current repository:

git config --global alias.identity '!sh -c "git config user.name \"$(git config user.$1.name)\" && git config user.email \"$(git config user.$1.email)\" && git config user.signingkey \"$(git config user.$1.signingkey)\"" -'

Usage (in a repo):

git identity <identifier>

PowerShell alternative (Windows users):

function Set-GitIdentity {
  param([string]$Identity)
  git config user.name (git config --get "user.$Identity.name")
  git config user.email (git config --get "user.$Identity.email")
  git config user.signingkey (git config --get "user.$Identity.signingkey")
}

Usage (in a repo):

Set-GitIdentity <identifier>

Add the PowerShell function to your PowerShell profile ($PROFILE) if you want it available in every session.

Creating identities

An identity has

• an identifier (e.g. work, personal)
• a name (e.g. Mike)
• an email (e.g. mike@business.com, mike@personal.dev)
• a private (e.g. ~/.ssh/id_ed25519) and a public (e.g. ~/.ssh/id_ed25519.pub) key

Generating an SSH key pair

Run the following command to create an ed25519 (recommended) key for each identity. Use -f to set a custom filename so keys don't overwrite each other:

ssh-keygen -t ed25519 -C <email> -f <path/to/key>

Follow the prompts and choose a passphrase you can remember (recommended). If you prefer no passphrase, press Enter when prompted.

Important

Keep the private key (path/to/key) secret. The public key (path/to/key.pub) may be shared with anyone.

Configuring an identity

Create an identity with name, email and signing key:

git config --global user.<identifier>.name <name>
git config --global user.<identifier>.email <email>
git config --global user.<identifier>.signingkey <path/to/key.pub>

Connecting to hosting services

To connect with hosting services, an identity gets a connection per remote.

SSH host entries

In ~/.ssh/config add an entry per connection (identity/host) to select which private key to use when connecting. Use the private key file in IdentityFile:

Host <connection>
	HostName <host ip or domain>
	PreferredAuthentications publickey
	IdentityFile <path/to/key>

To now reference a repository (e.g. for cloning), use git@<connection>:owner/repo.git as the remote.

Popular hosting services

GitHub: Add SSH keys

1. Go to Settings → Access → SSH and GPG keys and add a new SSH key with the following properties:

   • Title: Name the connection
   • Key Type: Authentication Key
   • Key: Paste the public SSH key

2. Add another SSH key:

   • Title: Name the connection
   • Key Type: Signing Key
   • Key: Paste the public SSH key

GitLab: Add SSH keys

1. Go to Edit profile → SSH Keys and add a new SSH key with the following properties:

   • Title: Name the connection
   • Usage type: Authentication & Signing
   • Key: Paste the public SSH key

Codeberg: Add SSH keys

1. Go to Settings → SSH / GPG Keys and add a new SSH key with the following properties:

   • Key name: Name the connection
   • Content: Paste the public SSH key

Verify connection

Verify that your SSH key was added correctly:

ssh -T git@<connection>

Tips

To avoid re-entering a passphrase every time, add your private key to an agent for the session:

ssh-add <path/to/key>

Example

In this example, two identities will be created:

• Mike's business identity:
  • identifier: business
  • name: Mike
  • email: mike@business.com
  • private key at ~/.ssh/id_25519_business
  • public key at ~/.ssh/id_25519_business.pub
  • connection github-business to GitHub
• Mike's personal identity:
  • identifier: personal
  • name: Mike
  • email: mike@personal.dev
  • private key at ~/.ssh/id_25519_personal
  • public key at ~/.ssh/id_25519_personal.pub
  • connection github-personal to GitHub
  • connection gitlab-personal to GitLab

Generating SSH key pairs

Run the following:

ssh-keygen -t ed25519 -C mike@business.com -f ~/.ssh/id_25519_business
ssh-keygen -t ed25519 -C mike@personal.dev -f ~/.ssh/id_25519_personal

Configuring identities

Run the following:

git config --global user.business.name "Mike"
git config --global user.business.email "mike@business.com"
git config --global user.business.signingkey "~/.ssh/id_25519_business.pub"
git config --global user.personal.name "Mike"
git config --global user.personal.email "mike@personal.dev"
git config --global user.personal.signingkey "~/.ssh/id_25519_personal.pub"

Connecting to hosting services

Add the following to your SSH config file:

Host github-business
	HostName github.com
	PreferredAuthentications publickey
	IdentityFile ~/.ssh/id_25519_business
Host github-personal
	HostName github.com
	PreferredAuthentications publickey
	IdentityFile ~/.ssh/id_25519_personal
Host gitlab-personal
	HostName gitlab.com
	PreferredAuthentications publickey
	IdentityFile ~/.ssh/id_25519_personal

In the business GitHub account:

1. Settings → Access → SSH and GPG keys and add a new SSH key:

   • Title: Mike's PC
   • Key Type: Authentication Key
   • Key: Content of ~/.ssh/id_25519_business.pub

2. Add another SSH key:

   • Title: Mike's PC
   • Key Type: Signing Key
   • Key: Content of ~/.ssh/id_25519_business.pub

In the personal GitHub account:

1. Settings → Access → SSH and GPG keys and add a new SSH key:

   • Title: Mike's PC
   • Key Type: Authentication Key
   • Key: Content of ~/.ssh/id_25519_personal.pub

2. Add another SSH key:

   • Title: Mike's PC
   • Key Type: Signing Key
   • Key: Content of ~/.ssh/id_25519_personal.pub

In the personal GitLab account:

1. Edit profile → SSH Keys and add a new SSH key:

   • Title: Mike's PC
   • Usage type: Authentication & Signing
   • Key: Content of ~/.ssh/id_25519_personal.pub

References

• Micah Henning - Setting Up Git Identities
• GitHub Docs - Generating a new SSH key and adding it to the ssh-agent
• GitHub Docs - Adding a new SSH key to your GitHub account
• GitLab Docs - Use SSH keys to communicate with GitLab
• Codeberg Docs - Adding an SSH key to your account