Chapter 32. Users and Groups

Chapter 32. Users and Groups

32.1. User and Group Configuration
32.1.1. Adding a New User
32.1.2. Modifying User Properties
32.1.3. Adding a New Group
32.1.4. Modifying Group Properties
32.2. User and Group Management Tools
32.2.1. Command Line Configuration
32.2.2. Adding a User
32.2.3. Adding a Group
32.2.4. Password Aging
32.2.5. Explaining the Process
32.3. Standard Users
32.4. Standard Groups
32.5. User Private Groups
32.5.1. Group Directories
32.6. Shadow Passwords
32.7. Additional Resources
32.7.1. Installed Documentation

The control of users and groups is a core element of Red Hat Enterprise Linux system administration.

Users can be either people (meaning accounts tied to physical users) or accounts which exist for specific applications to use.

Groups are logical expressions of organization, tying users together for a common purpose. Users within a group can read, write, or execute files owned by that group.

Each user and group has a unique numerical identification number called a userid (UID) and a groupid (GID), respectively.

A user who creates a file is also the owner and group owner of that file. The file is assigned separate read, write, and execute permissions for the owner, the group, and everyone else. The file owner can be changed only by the root user, and access permissions can be changed by both the root user and file owner.

Red Hat Enterprise Linux also supports access control lists (ACLs) for files and directories which allow permissions for specific users outside of the owner to be set. For more information about ACLs, refer to Chapter 14, Access Control Lists.


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