How to Manage Multiple Git Identities and Commit Signing

Working with multiple Git identities—especially when balancing personal and professional repositories—can be cumbersome if not handled properly. Fortunately, Git provides straightforward ways to maintain distinct identities and securely sign commits using SSH.

Organizing Your Project Directories

First things first: organize your repositories clearly. Create separate directories to distinguish between your work-related and personal projects:

• ~/Work for professional projects.
• ~/Projects for personal endeavors.

Ensure you also update paths in VS Code and shell aliases to reflect these directories.

Configuring Conditional Git Identities

Git supports conditional configurations, allowing automatic switching between identities based on the directory context.

Step 1: Create a Work-Specific Git Config

Make a separate config file (~/.gitconfig-work) dedicated to work-related repositories:

[user]
  name  = Your Work Name
  email = you@company.example.com

Step 2: Conditionally Include the Work Config

Edit your main ~/.gitconfig to include your work-specific configuration conditionally:

[user]
  name  = Your Personal Name
  email = you@personal.example.com

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

With this setup, Git automatically applies your work identity whenever you operate within the ~/Work directory, and defaults to your personal identity elsewhere.

Commit Signing with SSH Keys

Why SSH instead of GPG? Simplicity and convenience. Using SSH keys for commit signing streamlines the process significantly.

Generate a Dedicated SSH Signing Key

Create an SSH key specifically for signing your commits:

ssh-keygen -t ed25519 -f ~/.ssh/git_commit_signing -C "commit-signing@yourdomain"

Configure Git to Sign Commits

Edit your global Git configuration to enable commit signing with the newly generated SSH key:

[commit]
  gpgSign = true
[user]
  signingKey = ~/.ssh/git_commit_signing
[gpg]
  format = ssh

This single signing key simplifies your commit signing workflow across both personal and professional repositories.

Adding Your Signing Key to GitHub and GitLab

To ensure your commits show as “Verified” on GitHub and GitLab:

1. Copy your public SSH signing key:

cat ~/.ssh/git_commit_signing.pub

2. Add this key to your GitHub and GitLab account settings under “SSH Keys” or “Signing Keys.”

Locally Verify Your Signed Commits (Optional)

To verify your commits locally:

Step 1: Create an Allowed-Signers File

Define the allowed signers in ~/.config/git/allowed_signers:

you@company.example.com ssh-ed25519 AAAAC3...
you@personal.example.com ssh-ed25519 AAAAC3...

Step 2: Configure Git to Recognize the Allowed Signers File

Add the following to your global Git config:

[gpg "ssh"]
  allowedSignersFile = ~/.config/git/allowed_signers

Step 3: Verify Commits

Use this command to confirm commit verification:

git log --show-signature

Your commits should now display clearly as signed and verified.

Conclusion

By leveraging conditional Git configurations and SSH for signing, you simplify identity management and enhance security. Whether collaborating professionally or working on personal projects, this method ensures clear distinctions between your identities and keeps your commits trustworthy.

Happy coding! 🚀

Additional Resources

• Git Documentation: Conditional Includes
• GitHub Docs: Signing commits with SSH keys
• GitLab Docs: Add an SSH Key