Red Hat Enterprise Linux 5 Administration Unleashed

110CHAPTER 4Understanding Linux ConceptsFIGURE 4.4Graphical Version of the Display Configuration ToolBecoming the Root UserAs you learned in Chapter 2 it is important to log in with your user account instead of asthe root user when performing day-to-day tasks. Some of the graphical administrationtools will prompt you for the root password if you try to run them as a regular user. But,what if you are logged in as a user and need to perform an operation only the root usercan do? It would be time consuming to close all your open windows, log out of thegraphical desktop, log back in as root, execute root-only commands, log out again, andthen log back in with your user account.Instead, you can temporarily start a terminal session as root. From a shell prompt, executethe following command to temporarily become the root user:su -Notice the space and then a hyphen after the su command. These are extremely importantparts of the command. Without it, you have root privileges but you don’t inherit anyof the environment variables of the root user, including the important PATH variablepreviously discussed. Without the proper PATH that includes /sbin/ and /usr/sbin/, itwill appear as if many administrative commands don’t exist. After executing the su -command, you will be prompted to enter the root password before being granted access.If the correct root password is entered, you will notice that the prompt changes to showthat the root user is the currently logged-in user.When you no longer need to be root, type the exit command and then press Enter toreturn to your user shell.