Authenticate using SSH keys

Client machine:

$ cd to $HOME/.ssh
$ ssh-keygen -t dsa
<enter>, <enter> and <enter>

Resuts will be stored in id_dsa and id_dsa.pub.

Copy id_dsa.pub to server.

Server:

$ cat id_dsa.pub >> $HOME/.ssh/authorized_keys

This configuration allows a user to login from a client machine to the server without a password, using SSH key authentication, which is useful for automated scripts.