Passphrases
-----------

Avoid passwords on given hosts.
* generation: 
  create a private/public key pair in ~/.ssh/id_dsa{,.pub}
  $ ssh-keygen -t dsa -b 2048
* authentication: 
  copy the public key to the remote machine
  $ scp ~/.ssh/id_dsa.pub remote:
  append the key to the ~/.ssh/authorized_keys
  $ cat ~/id_dsa.pub >> ~/.ssh/authorized_keys

Secure login without interaction.
* avoid typing your loooong pass phrase every time
  $ ssh-add

Obtain the fingerprint from a public key.
  $ ssh-keygen -l -f rsa_key.pub