Graphical User Interface: Today, computers have an operating system which is called GUI’s. A GUI (Graphical User Interface) operating system is one which is capable of executing the commands by displaying a menu from which the user can select a command using the mouse. The GUI features of LINUX is known as the X-window system or simply X (this x- window does not mean the Microsoft’s Windows operating system). The GUI is a bitmapped display, while the command line interface is character-based display. The X Free 86 is the Red Hat’s version of the x-window system. This x-window system was created in 1984 at the Massachusetts Institute of Technology (MIT). In the x-window system, several windows can be opened, each running a different application.

The x-window system works on client-server technology. The x-server is a process that displays information from applications (xclients) using the x-GUI. Any application/program that makes requests of the x-server will become the x-client. Some systems have a graphic login that automatically starts the x-server when the system boots.

Linux is a multi-user operating system. It means multiple users can work on it and to maintain the security among different users we need to login in Linux by giving user name and password. After the computer boot and the operating system has started, the operating system asks for user name and password. On the login window, there are several buttons with various functions; you need to give user name and password to start with the Linux desktop and ignore the other buttons. Linux allows us to work with different desktop environments like KDE, GNOME, etc. By default, Red Hat Linux starts you off with a GNOME desktop.