Understanding System Administration

Red Hat Linux, like other UNIX systems, was intended for use by more than one person at a time. Multiuser features allow many people to have accounts in Red Hat Linux, with their data kept secure from others. Multitasking allows many people to use the computer at the same time. Sophisticated networking protocols and applications make it possible for a Red Hat Linux computer to extend its capabilities to network users and computers around the world. The person assigned to manage all of this stuff is referred to as the system administrator.
Even if you are the only person using a Red Hat Linux system, system administration is still set up to be separate from other computer use. To do most tasks, you need to be logged in as the root user (also referred to as the super user). Other users cannot change, or in some cases, even see some of the configuration information for a Red Hat Linux system. In particular, security features such as passwords are protected from general view.

Using the root Login
The root user has complete control of the operation of your Red Hat Linux system. That user can open any file or run any program. The root user also installs applications and adds accounts for other people who use the system.
When you first install Red Hat Linux, you should have added a password for the root user. You need to remember and protect this password. You will need it to log in as root or to obtain root permission while you are logged in as some other user. The home directory for the root user is /root. That and other information associated with the root user account is located in the /etc/passwd file. Here is what the root entry looks like in the /etc/passwd file:
root:x:0:0:root:/root:/bin/bash
This shows that for the user named root, the user ID is set to 0 (root user), the group ID is set to 0 (root group), the home directory is /root, and the shell for that user is /bin/bash. You can change the home directory or the shell used, if you like, by simply editing the values in this file.
Aliases for the rm, cp, and mv commands allow those commands to be run with the −i option. This prevents massive numbers of files being removed, copied, or moved by mistake. The −i option causes each deletion, copy, or move to prompt you before the actual change is made.