Chapter Summary

As with many operating systems, your access to a Linux system is authorized when you log in. You enter your username in response to the login: prompt, followed by a password. You can change your password any time while you are logged in. Choose a password that is difficult to guess and that conforms to the criteria imposed by the utility that changes your password.

The system administrator is responsible for maintaining the system. On a single-user system, you are the system administrator. On a small, multiuser system, you or another user act as the system administrator, or this job may be shared. On a large, multiuser system or network of systems, there is frequently a full-time system administrator. When extra privileges are required to perform certain system tasks, the system administrator logs in as the root user by entering the username root and the root password; this user is called Superuser or administrator. On a multiuser system, several trusted users may be given the root password.

Do not work as Superuser as a matter of course. When you have to do something that requires Superuser privileges, work as Superuser for only as long as you need to; then revert to working as yourself as soon as possible.

The man utility provides online documentation on system utilities. This utility is helpful both to new Linux users and to experienced users who must often delve into the system documentation for information on the fine points of a utility's behavior. The info utility helps the beginner and the expert alike. It includes a tutorial on its use and documentation on many Linux utilities.