1.   What is shell?

ans: a shell is a computer program which exposes an operating system's services to a human user or other program.

2.   What is terminal?

ans: terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system.

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

ans: GUI because we don't have toremember and type command. 

4.   What defines a user account?

ans: The account which we use to access a computer.

5.   What is root user?

ans: Root user have access to the root means he can perform all the function of an OS.

6.   What is general purpose user?

ans: By using general pupose user we can access those lower privilage comand.

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

ans: root user have all the access of an operating system but general purpose user does not. 

8.   What is the meaning of sudo?

ans: super user do

9.   What is the meaning of su?

ans: sudo.

10.              Why we use sudo?

ans : To get access to root directories.

11.              Why we use su?

ans: su use for privilage accesss for a targeted accout.

12.              How to create a user account?

ans: -$ sudo adduser sefat

13.              How to delete a user?

ans: -$ sudo deluser sefat

14.              How to login into a user account?

ans: -$ sudo adduser login

15.              How to logout from a user account?

ans: -$ logout

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

ans: 2 times.

17.              How to exit from root?

ans: logout/ exit

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

ans: To add a new user.

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

ans: To delete a specific user.

20.              What is the meaning of sudo su?

ans: super user do and super user.