It is clear now from the previous chapters that Nmap Script Engine and Nessus' Compliance Audit policy are an important part of both tools to perform comprehensive audits and checks. It is very important for a user to understand the workings of these components and the various techniques to customize them in order to perform specific operations. In this chapter, we will look at the details of Nmap Script Engine and Nessus Audit file compositions in order to create custom files and perform specific operations.