2
Chapter 1
Binaries
This term refers to files that can be executed, similar to
executables in Windows. Binaries
generally reside in the /usr/bin or
usr/sbin directory and include utilities such as
ps
,
cat
,
ls
, and
ifconfig
(we’ll touch on all of four of these in this chapter) as well as applica-
tions such as the wireless hacking tool aircrack-ng and the intrusion
detection system (IDS) Snort.
Case sensitivity
Unlike Windows, the Linux filesystem is case sensi-
tive.
This means that Desktop is different from
desktop, which is different
from
DeskTop. Each of these would represent a different file or directory
name. Many people coming from a Windows environment can find this
frustrating. If you get the error message “file or directory not found”
and you are sure
the file or directory exists, you probably need to check
your case.
Directory
This is the same as a folder in Windows. A directory pro-
vides a way of organizing files, usually in a hierarchical manner.
Home
Each user has their own
/home directory,
and this is generally
where files you create will be saved by default.
Kali
Kali Linux is a distribution of Linux specifically designed for
penetration testing. It has hundreds of tools preinstalled, saving you
the hours it would take to download and install them yourself. I will be
using the latest version of Kali at the time of this writing: Kali 2018.2,
first released in April 2018.
root
Like
nearly every operating system, Linux has an administrator
or superuser account, designed for use by a trusted person who can do
nearly anything on the system. This would include such things as recon-
figuring
the system, adding users, and changing passwords. In Linux,
that account is called
root. As a hacker or pentester, you will often use
the root account to give yourself control over the system. In fact, many
hacker tools require that you use the root account.
Script
This is a series of commands run in an interpretive environ-
ment that converts each line to source code.
Many hacking tools are
simply scripts. Scripts can be run with the bash interpreter or any of
the other scripting language interpreters, such as Python, Perl, or Ruby.
Python is currently the most popular interpreter among hackers.
Shell
This is an environment and interpreter for running commands
in Linux. The
most widely used shell is bash, which stands for
Bourne-
again shell, but other popular shells include the C shell and Z shell. I
will be using the bash shell exclusively in this book.
Terminal
This is a command line interface (CLI).
With those basics behind us, we will attempt to methodically develop
the essential Linux skills you’ll need to become a hacker or penetration tes-
ter.
In this first chapter, I’ll walk you through getting started with Kali Linux.
