Two GitHub accounts, one computer · step 2 of 6

Configuring .gitconfig

This step is identical on Windows, macOS, and Linux.

1. The main ~/.gitconfig file

Find or create ~/.gitconfig (on Windows that’s usually C:\Users\YOURNAME\.gitconfig) and add includeIf sections pointing at your project folders. Substitute your own drive letter and path:

[includeIf "gitdir:D:/Projects/user1/"]
    path = .gitconfig-user1
[includeIf "gitdir:D:/Projects/user2/"]
    path = .gitconfig-user2

On macOS/Linux the paths look similar, e.g.:

[includeIf "gitdir:~/Projects/user1/"]
    path = .gitconfig-user1
[includeIf "gitdir:~/Projects/user2/"]
    path = .gitconfig-user2

Details that most commonly break this mechanism:

• The path in gitdir: must end with a trailing slash /.
• The drive letter and casing must match your actual folder layout exactly — if the folder is Projects and your config says projects, includeIf may not fire on some systems.
• Relative paths in path = (e.g. .gitconfig-user1) are resolved relative to the folder containing this .gitconfig — usually your home directory.
• On Windows, use / in paths, not \.

2. Per-account config files

Create ~/.gitconfig-user1:

[user]
    name = User1
    email = user1@example.com
[core]
    sshCommand = "ssh -i ~/.ssh/id_ed25519_user1 -o IdentitiesOnly=yes"

And similarly ~/.gitconfig-user2:

[user]
    name = User2
    email = user2@example.com
[core]
    sshCommand = "ssh -i ~/.ssh/id_ed25519_user2 -o IdentitiesOnly=yes"

On Windows, give sshCommand the full path with slashes, e.g. C:/Users/YOURNAME/.ssh/id_ed25519_user1.

The -o IdentitiesOnly=yes flag matters — without it, the SSH agent may try a different key before reaching for the one explicitly given.

3. Sanity check before moving on

Go into the user1 project folder and check where Git is pulling the identity from:

cd D:/Projects/user1/some-project
git config --show-origin --get user.email
git config --show-origin --get core.sshCommand

Both should point to .gitconfig-user1. If they show something else, the most common cause is a local .git/config inside this specific repository, which always overrides values from includeIf. Check:

cat .git/config

If there’s a [user] section with the wrong email, remove it:

git config --local --unset user.email
git config --local --unset user.name

The same can happen with core.sshCommand if it was ever set locally in this repo.

Next up — generating SSH keys and configuring the agent — pick your platform below.