Once you have logged in to your desktop, you can switch to different user without having to log out or end your current user session. On GNOME you use the User Switcher tool, a GNOME applet on the panel. For KDE you use the Switch User entry on the Main menu.
User Switcher: GNOME
On GNOME, the [...]
Like Unix, Linux can be generally divided into three major components: the kernel, the environment, and the file structure. The kernel is the core program that runs programs and manages hardware devices, such as disks and printers. The environment provides an interface for the user. It receives commands from the user and sends those commands [...]