Multiple GitHub Accounts with Automatic SSH Key Selection

This approach allows you to use different ssh keys with multiple github accounts only with git config, and without any intrusive changes in repos / urls.

This approach allows for routing of SSH keys based on URL regex in the global gitconfig (no SSH config required).

From what I can see min requirements are Git 2.36+ as it introduced hasconfig support.

Why this approach

This solution has a different approach to other options available, including:

• Different ssh hosts (e.g. git clone [email protected]:...)
• Different folder paths (i.e. using gitdir from path)
• Manual git config local overrides of sshCommand to point to different keys
• Scripts / extra tools to switch accounts (e.g. which basically override one of the above)

All solutions have pros and cons; in my case the least intrusive approach is the URL regex routing provided below.

Setup

1. Create Account-Specific Git Config

Create a config file that will be imported specifically for relevant repos.

Here you need to point to the respective SSH key for these seleted repos.

~/.gitconfig-work:

[core]
    sshCommand = ssh -i ~/.ssh/id_rsa-work -o IdentitiesOnly=yes # YOUR SSH KEY HERE
[user]
    name = Your Name
    email = [email protected]

2. Update Main Git Config

Now you can define a) a default ssh key for "all the rest", and b) the specific url paths to apply the custom path for.

~/.gitconfig:

# Default personal settings
[user]
    name = Your Name
    email = [email protected]

# This points to the default ssh key
[core]
    sshCommand = ssh -i ~/.ssh/id_rsa -o IdentitiesOnly=yes # YOUR DEFAULT SSH PATH HERE

# Auto-detect work organizations
[includeIf "hasconfig:remote.*.url:*github.com:companyname**/*"]
    path = ~/.gitconfig-work
[includeIf "hasconfig:remote.*.url:*github.com*work-username*"]
    path = ~/.gitconfig-work

3. Remove Any Existing (Conflicting) SSH Config

Important: Remove or comment out any IdentityFile entries for github.com in ~/.ssh/config:

# REMOVE or comment these out:
# Host github.com
#     IdentityFile ~/.ssh/id_rsa

Usage

Once this is done, you can clone any repository normally - the correct SSH key is selected automatically:

# Uses personal key automatically
git clone [email protected]:personal-user/repo.git

# Uses work key automatically
git clone [email protected]:company-org/repo.git

How It Works

1. Git scans remote URLs when loading config
2. If URL matches work patterns it includes work config
3. Work config overrides SSH key via core.sshCommand
4. SSH config conflicts are avoided by removing competing entries

Add More Organizations

Simply add more includeIf patterns:

[includeIf "hasconfig:remote.*.url:*github.com*another-org*"]
    path = ~/.gitconfig-work