git: Configuring SSH Keys per repository

git ssh key ssh command GIT_SSH_COMMAND core.sshCommand

2 min read | by Jordi Prats

For Git users, the Secure Shell (SSH) protocol is the go-to choice for authenticating and communicating with remote repositories. How can we configure the correct SSH key to use?

Global Configuration via ~/.ssh/config

To configure a single key (single account) we can just use or update the default SSH key: ~/.ssh/id_rsa or use ~/.ssh/config to specify a different SSH for (or any other git repository) like so:

    IdentityFile ~/.ssh/github
    IdentitiesOnly yes

With this configuration it would use the key located in ~/.ssh/github instead of the default one just for

SSH keys for multiple accounts

When we have multiple accounts we might need a little more flexibility in order to choose for each repository which SSH key to use.


We can achieve this using the envionronment variable GIT_SSH_COMMAND.

We just need to specify the ssh command to use, so if we set the ssh key to use using the -i flag we would be able to select the appropriate SSH key to use for each git command. For example:

GIT_SSH_COMMAND="ssh -i ~/.ssh/account_A" git clone example

And use another key byt simply updating GIT_SSH_COMMAND:

GIT_SSH_COMMAND="ssh -i ~/.ssh/account_B " git push

git core.sshCommand

Since Git version 2.10.0, you can also use the core.sshCommand setting. There's no more need to use the environment variable. Here's how you clone a repo and set this configuration at the same time.

We use configure this setting for each command with the -c option:

git clone -c "core.sshCommand=ssh -i ~/.ssh/account_C"

Global configuration

Configure it globally:

git config --global core.sshCommand "ssh -i ~/.ssh/account_C"

SSH key per git repository

We can set it up for each repository as following:

git config core.sshCommand "ssh -i ~/.ssh/account_C"

Since you are configuring a different ssh key per repository (aka a different username) you'll want to update the for that repository as well:

git config

Posted on 26/10/2023