To specify the private SSH key to use when executing shell commands on Git, you need to follow these steps:
Locate the private key file on your local machine. The private key is typically stored in a file with a name like "id_rsa" or "id_dsa" in the .ssh directory in your home directory.
Once you have located the private key file, you need to add it to your SSH agent. You can do this by running the following command in your terminal:
Now, you can specify the private key to use when executing shell commands on Git by setting the GIT_SSH_COMMAND environment variable. You can do this by running the following command in your terminal:
export GIT_SSH_COMMAND="ssh -i /path/to/private/key"
This sets the GIT_SSH_COMMAND environment variable to the SSH command with the -i option, which specifies the location of the private key file.
You can then execute your Git command as usual, and it will use the specified private key for authentication. For example, to clone a repository using SSH authentication, you can run the following command:
git clone firstname.lastname@example.org:user/repo.git
This will use the private key you specified to authenticate with the Git server.