Learning Red Hat Linux, Second Edition

Chapter 4. How Linux Works

Before you can effectively use a desktop environment, you need to know some Linux fundamentals. This chapter explains basic Linux concepts that underlie graphical and nongraphical system use. It describes Linux user accounts and how Linux organizes data as filesystems, directories, and files. This chapter also explains how to use the X Window System (often known simply as X). Because both GNOME and KDE are built atop X, an understanding of X is central to using either desktop environment.

User Accounts

Like other multiuser operating systems, such as Windows NT/2000, Linux uses user accounts to identify users and allocate permissions. Every Linux system has a special user, known as the root user. The root user is analogous to the Windows NT/2000 user known as Administrator. The root user can perform privileged operations that are forbidden to other users. For instance, most system administration operations can be performed only by the root user. By default, the user ID associated with the root user is root.

You should be judicious in your use of the root account. For instance, you should safeguard the associated password, so that no one uses it to compromise your system. Also, you should log in as the root user only when performing privileged operations. Following this advice will help you avoid disasters such as accidentally deleting important files that are protected against access by ordinary, non-root users.