Chapter 5: Securing Systems with Users, Groups, and Permissions

Security is a key part of managing a system, and understanding the security concepts in order to provide the right access to the right resource to the right user, or group of users, is required for any system administrator.

In this chapter, we will review the basics of security in Red Hat Enterprise Linux (RHEL). We will add new users to a system and change their attributes. We will also add a user to a group, and reviewing groups before making changes will be seen in this chapter. We shall review how to handle user passwords and changing the age requirements for them, locking and/or restricting user access. We will use sudo as a way to assign admin privileges to different users in the system (and even disable the root account). We will also take a deeper look into file permissions and how to change them, using an extended capability to enable commands to be run with a different user or group or simplify group collaboration...