nessus-xmlrpc is a Ruby library for the Nessus XML-RPC interface. It comes with an example command line program that shows how easy it is to interact with the Nessus scanner.
You can download it from the following link: https://packetstormsecurity.com/files/download/86989/nessus-xmlrpc-0.3.tar.gz
Source: https://packetstormsecurity.com/files/86989/Nessus-XML-RPC-Ruby-Library-0.3.html