Automating Root Logins
Most administration tasks require root privileges at some point. Tasks are easy to run as root on a single machine, but the situation becomes more complex in multisystem environments where one machine may need to run a remote process as root or copy a file as root to another machine. In interactive situations, the administrator can simply log in to remote machines and su to root using root's password; this option, however, doesn't work for automated processes. You don't want to put a root password in a script file, no matter how well that file is protected.
Using the Berkeley r-commands Without a Password
One of the oldest methods for executing commands on a remote system is by using the Berkeley r-commands, named for their ...