1.   What is shell?

Ans: shell is a computer program that exposes an operating system's services to a human user or another program.

2.   What is terminal?

Ans: The terminal is an interface that allows you to access the command line.

3.   What is user friendly in between terminal and GUI & why?

Ans: GUI, because you can do things using a mouse, no need for typing commands.

4.   What defines a user account?

Ans: A user account is an identity created for a person in a computer or computing system.

5.   What is root user?

Ans: The root is the user name or account that by default has access to all commands and files on a Linux or other Unix-like operating system

6.   What is general purpose user?

Ans: A general-purpose computer is one that, given the appropriate application and required time, should be able to perform the most common computing tasks. Personal computers, including desktops, notebooks, smartphones, and tablets, are all examples of general-purpose computers.

7.   What are the difference between root user and general purpose user?

Ans: The root user is basically equivalent to the Administrator user on Windows – the root user has maximum permissions and can do anything to the system. Normal users on Linux run with reduced permissions – for example, they can't install software or write to system directories.

8.   What is the meaning of sudo?

Ans: Sudo is a program for Unix-like computer operating systems that allows users to run programs with the security privileges of another user.

Ans: The Unix command su, which stands for substitute user, is used by a computer user to execute commands with the privileges of another user account.

10. Why we use sudo?

Ans: The sudo command allows you to run programs with the security privileges of another user (by default, as the superuser). It prompts you for your personal password and confirms your request to execute a command by checking a file, called sudoers, which the system administrator configures.

11.  Why we use su?

Ans: For gaining administrator or root privileges on another account.

12. How to create a user account?

Ans: To create a new user account, invoke the user add command followed by the name of the user. When executed without any option, useradd creates a new user account using the default settings specified in the /etc/default/useradd file.

13. How to delete a user?

Ans:  Use "sudo userdel 'username'" command.

14. How to login into a user account?

Ans: Use "Sudo login 'username'" command.

15.  How to logout from a user account?

Ans: Use the 'logout' command.

16.  How many times it requires password for creating a user account?

Ans: Two.

17.  How to exit from root?

Ans: in the terminal. Or you can simply press CTRL + D. Show activity on this post. Just type exit and you will leave the root shell and get a shell of your previous user.

18. What is the meaning of sudo adduser {username}?

Ans: Create a new user with the specified username.

19. What is the meaning of deluser {username}?

Ans: Delete a user by the specified username.

Ans: Sudo su - The sudo command allows you to run programs as another user, by default the root user. If the user is granted with sudo assess, the su command is invoked as root. Running sudo su - and then typing the user password has the same effect the same as running su - and typing the root password.