SSH config

This tip has three goals:

• make ssh command shorter (ssh alex instead of ssh alex@alexComputer)
• avoid having to type password when using ssh
• forward you ssh keys so that you can use them while on another machine

Config file

Host alex
    HostName alexComputer
    User alex
    ForwardAgent yes

Host nick
    HostName nickComputer
    User nick
    ForwardAgent yes

Write this to .ssh/config.

Allow your ssh key on remote machines

For each machine you want to access, run the following command:

ssh-copy-id -i <path-to-my-key> <host>

In our case:

ssh-copy-id -i ~/.ssh/id_rsa alex
ssh-copy-id -i ~/.ssh/id_rsa nick

Note: since ~/.ssh/id_rsa is actually the default path for the ssh key, we can just use ssh-copy-id <host>

Check that agent forwarding works

SSH on one machine, and type SSH on one machine, and type ssh -T git@github.com, this should show you your Github username and not the host’s one. If this does not work, go back on your machine and type ssh-add -L, if you get no identity is available, try ssh-add .ssh/id_rsa and it should now work.