Practical Linux System Administration

Chapter 2. Working with Permissions and Privileged Accounts

For sysadmins, the CLI is home. Typing at the keyboard is standard fare. You’ll need to become comfortable with the command line, its idiosyncrasies, and its shortcuts—yes, there are command-line shortcuts. There’s a lot to learn about Linux at the command line. There are dozens of commands, each with dozens of options. Sure, you’ll only use a handful of commands and a limited number of options for each command, but you need to know how to find the options you need and how to use them when you need to.

The true power of the CLI is in its ease of use. The CLI was the first interface that users and programmers had with which to address their operating environments. The fact that the CLI is still in use some 50 years later is a testament to its power and usefulness to the sysadmin and user alike. This chapter teaches you to work at the command line as a regular user and as a root user. You also learn to set and modify file permissions and the effects that those permissions have on files.

Working as a Regular User

There are two user types on a Linux system: regular users and a root, or administrator, user. Regular users each receive their own home directory and somewhat limited system use. The root user also has a home directory (/root). Regular users have almost unlimited power in their own home directories to create, modify, remove, and manipulate files but have almost no power outside of that single location. Many system ...