As I’m always using ssh, copying or rsyncing files between all my servers I find it very annoying to always have to type in my login password. To avoid that, I exchanged my ssh keys so that all the authentication is done through those keys. To achieve that simply:

On the machine you want to have access from:

1. Generate a new key if you don’t already have one:

$ ssh-keygen

2. Copy the key accross to the other server:

$ cat ~/.ssh/id_rsa.pub | ssh user@target_machine cat - ">>" ~/.ssh/authorized_keys

Now when you want to ssh or scp or rsync user@target_machine you won’t need to use a password any more!