Users And Groups; User And Group Configuration - Red Hat ENTERPRISE LINUX 4 System Administration Manual

Chapter 32.

Users and Groups

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
Chapter 14, Access Control Lists.
to

32.1. User and Group Configuration

The User Manager allows you to view, modify, add, and delete local users and groups.
To use the User Manager, you must be running the X Window System, have root privileges, and have
the system-config-users RPM package installed. To start the User Manager from the desktop,
go to Applications (the main menu on the panel) => Administration => Users & Groups. You can
also type the command system-config-users at a shell prompt (for example, in an XTerm or a
GNOME terminal).
Figure 32.1. User Manager
To view a list of local users on the system, click the Users tab. To view a list of local groups on the
system, click the Groups tab.
To find a specific user or group, type the first few letters of the name in the Search filter field. Press
Enter or click the Apply filter button. The filtered list is displayed.
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