Say you have two github accounts. So you have different SSH keys. Github won't know which key relates to which account.
However, in your
~/.ssh/config file you can setup an alias that uses the correct
IndentityFile to send to github.
In that file, put this:
Host new_alias Hostname github.com User git IdentityFile ~/.ssh/id_rsa_new_identity
Now you can use
git remote origin git@new_alias:your_username/therepo.git Note the
: after the alias name. And the fact you're putting
git@ at the start.