"Linux provides two basic types of interface for you to use when working with your computer: GUI (graphical user interface) and CLI (command-line interface). An overview of the interface types is provided in Chapter 5. In this chapter, the most common type of interface, a GUI called a desktop, is discussed in detail. The CLI is discussed in detail in Chapter 7.
"Linux can start without a desktop, but most users prefer to have Linux start with a desktop. The installation instructions provided in Chapter 4 result in a desktop opening at startup. A desktop interface functions as the top of your desk, supplying an empty working surface and a set of tools..."