What exactly does ssh-add do?

Question

I recently reinstalled my laptop and found that 'git clone' wasn't working. I was consistently receiving Permission denied (publickey). errors.

The fix is documented on GitHub's SSH issues page: use ssh-add to tell SSH about the key I want to use to authenticate on GitHub.

My question is: under the hood, what does ssh-add actually do?

I've been meaning to expand my understanding of SSH for a while, & this seems like a good excuse to start :-)

Answer 1

ssh-add adds private key identities (from your ~/.ssh directory) to the authentication agent (ssh-agent), so that the ssh agent can take care of the authentication for you, and you don’t have type in passwords at the terminal.