Red Hat Linux 6: Visual QuickPro Guide

Setting Up Users and Groups

In Unix systems—including Linux—each file and process (a process is an activity started by a program) is owned. The owner of a file or process has the primary right to control it. These rights can be overridden only by the superuser, called root.

Each file has both an owner and a group owner. These owners can set the permissions on a file so that no one else can access it.

You may find it interesting to discover that there are users (and groups of users) on your Linux system who are not human. These include:

• daemon, which is both an owner and a group of owners of system software processes

• bin, who often owns the directories that contain system commands and executables

• sys, whose group members own such things as swap ...