There are two basic ways to get to a command shell (the program that provides the command line) when you need to run Linux commands directly:
Press Ctrl+Alt+Fx (that is, one of the function keys) to switch to one of the virtual consoles. Then you can log on and run commands to your heart's content. When you're done, press Ctrl+Alt+F7 to return to GNOME.
Open a command shell directly in GNOME by choosing Main Menu System Tools Terminal. This opens a command shell in a window on the GNOME desktop, as shown in Figure 24-3. Because this shell runs within the user account GNOME is logged in as, you don't have to log on. You just start typing commands. When you're done, type Exit to close the window.
Figure 24-3: Using a Terminal window to run Linux commands.