After the basics of Linux, it is time to learn the package management system of a Debian-based distribution. In such distributions, including Kali, the Debian package is the canonical way to make software available to end-users. Understanding the package management system will give you a great deal of insight into how Kali is structured, enable you to more effectively troubleshoot issues, and help you quickly locate help and documentation for the wide array of tools and utilities included in Kali Linux.
In this chapter, we will introduce the Debian package management system and introduce dpkg and the APT suite of tools. One of the primary strengths of Kali Linux lies in the flexibility of its package management system, which leverages these tools to provide near-seamless installation, upgrades, removal, and manipulation of application software, and even of the base operating system itself. It is critical that you understand how this system works to get the most out of Kali and streamline your efforts. The days of painful compilations, disastrous upgrades, debugging gcc, make, and configure problems are long gone, however, the number of available applications has exploded and you need to understand the tools designed to take advantage of them. This is also a critical skill because there are a number of security tools that, due to licensing or other issues, cannot be included in Kali but have Debian packages available for download. It is important that you know how to process and install these packages and how they impact the system, especially when things do not go as expected.
We will begin with some basic overviews of APT, describe the structure and contents of binary and source packages, take a look at some basic tools and scenarios, and then dig deeper to help you wring every ounce of utility from this spectacular package system and suite of tools.