How to use an alternate SSH key with Git

By default, Git only uses you primary SSH key when cloning. While there’s no way to get git to try alternate keys if the first key fails, there are a few ways you can force it to use a particular key on a per-repository basis.

Via ssh-agent

How to specify an alternate SSH key with git using ssh-agent

ssh-agent bash -c "ssh-add $KEY_FILE && git $COMMAND"

INFO

$KEY_FILE must be the full path of a private key (e.g., ~/.ssh/id_rsa or ~/.ssh/gpg_auth_key.pub).

This is useful for running multiple, one-off commands. Note that this method won’t work when used with GPG authentication subkeys.

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Via GIT_SSH_COMMAND

How to specify an alternate SSH key using the GIT_SSH_COMMAND variable

With a secret SSH key:

GIT_SSH_COMMAND="ssh -i $KEY_FILE -F /dev/null -o IdentityAgent=none" git $COMMAND

INFO

$KEY_FILE must be the full path of a private key (e.g., ~/.ssh/id_rsa or ~/.ssh/gpg_auth_key.pub).

IMPORTANT

If you’re running ssh-agent, then setting the config directive IdentityAgent=none is important as otherwise the key(s) already stored in the agent will take precedence over $KEY_FILE.

With KeePassXC or a GPG authentication subkey referenced using a public $KEY_FILE, setting IdentityAgent=none is unnecessary:

GIT_SSH_COMMAND="ssh -i $KEY_FILE -F /dev/null" git $COMMAND

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Via a config directive

How to specify an alternate SSH key as a Git config directive

With a secret SSH key:

git config core.sshCommand "ssh -i $PUBLIC_KEY_FILE -F /dev/null -o IdentityAgent=none"

INFO

$KEY_FILE must be the full path of a private key (e.g., ~/.ssh/id_rsa or ~/.ssh/gpg_auth_key.pub).

IMPORTANT

If you’re running ssh-agent, then setting the config directive IdentityAgent=none is important as otherwise the key(s) already stored in the agent will take precedence over $KEY_FILE.

With KeePassXC or a GPG authentication subkey referenced using a public $KEY_FILE, setting IdentityAgent=none is unnecessary:

git config core.sshCommand "ssh -i $PUBLIC_KEY_FILE -F /dev/null"

This is useful for ongoing work, but only works on existing repositories.

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