System Administration Guide: Basic Administration

What Are User Accounts and Groups?

One basic system administration task is to set up a user account for each user at a site. A typical user account includes the information a user needs to log in and use a system, without having the system's root password. User account information has the following components:

Component	Description
User name	A name that a user uses to log in to a system. This name is also known as a login name.
Password	A secret combination of characters that a user must enter with a user name to gain access to a system.
User's home directory	A directory that is usually the user's current directory at login. The user's home directory typically contains most of the user's files.
User initialization files	Shell scripts that control how the user's working environment is set up when a user logs in to a system.

Also, when you set up a user account, you can add the user to predefined groups of users. A typical use of groups is to set up group permissions on a file and directory, which allows access only to users who are part of that group.

For example, you might have a directory containing confidential files that only a few users should be able to access. You could set up a group called topsecret that includes the users working on the topsecret project. And, you could set up the topsecret files with read permission for the topsecret group. That way, only the users in the topsecret group would be able to read the files.

A special type of user account, called a role, is used to give selected users special privileges. For more information, see “Role-Based Access Control (Overview)” in System Administration Guide: Security Services.

A user or group can be a member of one or more projects. A project is an identifier that is used to chargeback system resources. For information on using projects, see “Projects and Tasks” in System Administration Guide: Resource Management and Network Services.