It's obviously more common for people today to learn how to use a computer via a graphical user interface, but graphical user interfaces entail extra software, and the more software we have on a server, the more resources that software consumes, and the more we expose our systems to security risks.
Graphical user interfaces also do not provide a good platform for automation, at least not remotely as well as command line interfaces do. Working on the command line, in what is know as a shell, is in fact programming the computer.
Fortunately, Linux, and many other Unix-like operating systems, have the ability to operate without graphical user interfaces. This is partly the reason why these operating systems have done so well in the server market.
In this section, our focus is learning the command line environment, how to use it, and what it offers.