Chapter 19. User and Group Management

Chapter Syllabus

19.1 Managing Users

19.2 Managing Groups

19.3 The Password File (/etc/passwd)

19.4 The Group File (/etc/group)

19.5 The Skeleton Directory (/etc/skel)

19.6 Using SAM for User and Group Management

A user must log into a system before starting to use it. The system administrator creates user accounts and assigns a login name and password to every user. Each user is a member of one or more groups. A group is a set of users that has something common among them. For example, people working in an accounts department may be in one group and those working in a support department may be in another group. The scheme of grouping is used for security purposes as discussed in Chapter 7.

User and group management is an ongoing system administration task, and this chapters covers procedures for creating and managing users and groups. They can be created either by using command-line utilities or with the help of SAM. Both of these methods will be discussed in this chapter. A number of operations are performed on user accounts, like enabling and disabling accounts, setting password expiration policy, managing group memberships, and so on. All user accounts and passwords are recorded in the /etc/passwd file. You will learn about the format of this file. The group information is present in the /etc/group file, and the format of this file will also be discussed. As these files are very important, you need to make sure that they are error free. You will learn some commands to check the consistency of these files. At the end of the chapter you will use SAM for user and group management.

After going through this chapter, you will be able to create new user and group accounts and manage the existing ones with the help of command-line utilities as well as with SAM.

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