From http://www.linuxproblem.org/art_9.html
a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys' b@B's password:
# For github case, just copy the public key from your machine (after keygen) # such as ~/.ssh/id_rsa.pub to the web interface # https://github.com/settings/keys