An average PC user would normally understand the ‘user’ concept of operating that PC. Every person that logs in to a computer system is recognized by that system as a “user”, and such a user has certain privileges (operations he or she can carry out) that is assigned to him/her automatically by the system.
This is a security feature built into computer operating systems to protect it against intrusion (to some extent anyway) – if somebody that is not supposed to have access to your computer with certain ‘high’ privilege they can alter your system settings and configurations that might harm your system. There are some cases where you might even be locked out of your system by an intruder. So restricting what a user can do on a computer system is very essential. And based on the different levels of privileges that can be granted to users, users of Linux systems can be categorized into different groups as necessary. Linux has a very developed and robust built-in user system. Based on privileges Linux user enjoy, they can be differentiated into two major categories; the super user and the regular user – or sometimes more or less like the “admin” and “guest” user accounts.
THE SUPER (#) USER
The supper user is also known as “root”. It is a special user account that has all the permissions on a Linux system – to modify, control and configure various resources on Linux. The root user is the administrator for Linux. It is with the privileges possessed that the root user ensures that that system is always running smoothly. root has the power, which is not limited, to creating and deleting other users or groups, installing and removing software packages, backing up the system, and many more. And because of the enormous power the root user possess, it is usually advised that a Linux system administrator should have an alternate (lesser privileged) user account when working on the system and only use the root access only when necessary. In fact for this reason Ubuntu Linux is designed in such a way that it is difficult for a user to log in as root – instead the sudo command is provided to perform any needed administrative functions. Since most of the work done in Linux are usually done using the command line interface (CLI), it is possible that a mistake can occur where the admin would run a deadly command that would harm or even destroy the computer system entirely. The root user is designated on the CLI with a ‘#’ sign. For a personal computer the root user is always the owner of the PC. This is not always the case in a large networked server environment.
REGULAR ($) USER:
The regular users are those who not root, but occasionally log in to Linux. Basically if you’re not root then you’re just a regular Linux user. For instance, if your sibling wants to type a school report or want to browse the internet with your Linux box you could just create a user account with his login details for him – as a regular user. And sometimes most Linux distros automatically create a guest account that other users can use to access the system with a limited (non-root) privileges. The $ is used to denote the regular user on the CLI.
Every user on Linux have some set of characteristics that distinguish one user from the other. They include username, password, and unique identification numbers (UID) and group ID (GID) which are generated by the system on creating the users. Other personal user information like email, real name, phone, address and so on, can also be added. The account information of all users is usually found in the /etc/passwd directory and can be viewed from the command line using;