L in u X ba sics for h acke rs g e t t I n g s t a r t e d w I t h

Adding Repositories to Your sources.list File
The servers that hold the software for particular distributions of Linux are 
known as repositories. Nearly every distribution has its own repositories of 
software—developed and configured for that distribution—that might not 
work well, or at all, with other distributions. Although these repositories 
often contain the same or similar software, they aren’t identical, and they 
sometimes have different versions of the same software or entirely different 
software.
You will, of course, be using the Kali repository, which has a large 
amount of security and hacking software. But because Kali specializes in 
security and hacking, it doesn’t include some specialty software and tools 
and even some run-of-the-mill software. It’s worth adding a backup reposi-
tory or two that your system can search through in case it doesn’t find it a 
specific software in the Kali repository. 
The repositories your system will search for software are stored in the 
sources.list file, and you can alter this file to define from which repositories 
you want to download software. I often add the Ubuntu repositories after 

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Chapter 4
the Kali repositories in my sources.list file; that way, when I request to down-
load a new software package, if it isn’t in the Kali repository, my system may 
find it in the Ubuntu repository. 
You can find the sources.list file at /etc/apt/sources.list and open it with any 
text editor. I’ll again be using Leafpad. To open the sources.list file, enter the 
following into your terminal, replacing 
leafpad
with the name of your editor:
kali >leafpad /etc/apt/sources.list
After entering this command, you should see a window like the one in 
Figure 4-1, with a list of Kali’s default repositories.
Figure 4-1: Kali’s default repositories in sources.list
Many Linux distributions divide repositories into separate categories. 
For instance, Debian breaks out its repository categories as follows: