Practical Linux System Administration

Chapter 4. Managing Users

As a system administrator, you’ll spend a significant portion of your time managing users. You’ll also spend time troubleshooting user problems that aren’t account- or permissions-related, such as connectivity problems, broken applications, data corruption, training issues, security issues, and user-created problems.

Managing users covers the following tasks:

• Creating user accounts

• Modifying user accounts

• Removing user accounts

• Granting access to files and directories

• Restricting access to files and directories

• Enforcing security policies

• Setting permissions on files and directories

Some user management tasks can be learned from this book, while others are purely experiential and on-the-job training for you. No two user environments are exactly alike, and no two user experiences are exactly alike. In this chapter, you learn some preemptive user management methods, but problems still occur. The techniques you learn in this chapter will get you started on being able to handle an array of user-related problems.

User and Group ID Numbering Conventions

There are some guidelines associated with creating and maintaining user accounts on Linux systems, as shown in Table 4-1. These aren’t hard and fast rules, but they’re generally followed on most corporate systems.

Table 4-1. Numbering conventions for user and group accounts

UID	GID	Description
0	0	Root
1–999	1–999	System/service accounts
1000+	1000+	User accounts

User account UID ...