Filesystem Hierarchy Standard (FHS) defines the directory structure and directory contents in Linux operating systems. Based on Debian-package compliance, Kali Linux follows FHS. This means it allows all Linux users to easily locate binaries, support files, libraries, etc. Kali Linux has more than 300 penetration testing tools and you will be able to call any tool from anywhere on the system as every application is included in the system path. Unlike Backtrack, you do not have to navigate, just type the command name of the tool in root terminal and you are set to go.