Kali Linux “So, what’s the difference between BackTrack and Kali?” you might be asking. Unfortunately for us, that’s not a simple question to answer. It’s a mix between “everything” and “not much”, depending on how you used BackTrack. From an end user perspective, the most obvious change would be the switch to Debian and an FHS-compliant system. What this means is that instead of having to navigate through the /pentest tree, you will be able to call any tool from anywhere on the system as every application is included in the system path. However, there’s much hidden magic in that last sentence.