Password-less login

From HOSTA to HOSTB. Create key without passphrase:

HOSTA% ssh-keygen                                     
Generating public/private rsa key pair.
Enter file in which to save the key (/home/cbo/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/cbo/.ssh/id_rsa.
Your public key has been saved in /home/cbo/.ssh/

And copy over to HOSTB

HOSTA% cat .ssh/ | ssh HOSTB 'cat >> .ssh/authorized_keys'

Human readable known_hosts

In /etc/ssh/ssh_config:

HashKnownHosts no