Behind the pretty graphical interfaces of a Linux-based operating system such as Raspbian, is the console.
The console is the most basic way of communicating with the innards of the Raspbian operating system. The console's history started at the very beginning of computing where the interface to a computer was a keyboard and a teletype machine. At that time, operators would type a command and the result would be printed in front of them.
A teletype machine
Fortunately, with the development of computer monitors, we no longer need a typewriter to communicate with our computer and there are many different ways in which this can be done. You already learned how to use the Raspberry Pi's graphical user interface Xfce, and this chapter will run you through how you can use the built-in console terminal application called bash.
The Bourne again shell (bash) is a console shell developed by the GNU project that was released in 1989. Originally written by Brian Fox, it has become the de facto standard and is used by default in almost all Linux operating systems, OS X, Novell NetWare, Android, as well as on Windows. The bash was inspired by the sh shell, which was extremely popular around the time bash was created.
The bash shell was written as an open source replacement to the Bourne shell that was the default command-line interpreter for Unix. The bash supports many features, including the autocompletion of commands and filename wildcards.