1. What is shell?   Answer: Shell is an environment in which we can run our commands, programs, and shell scripts.

2. What is terminal?

Answer: Terminals, also known as command lines or consoles, allow us to accomplish and automate tasks on a computer without the use of a graphical user interface.

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

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

4. What defines a user account?

Answer: Linux is multi-user system. This means more than one person can use the Linux. With the help of various software servers, configurations, and commands, multiple users can use Linux.

5. What is root user?

Answer: The root is the user 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?

Answer: General purpose user has limited access to Linux. Day-to-day tasks can be executed using this account but the system can not be modified with this account.

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

Answer: The main difference between general purpose and root user is that root user can make changes to the system while the general purpose user can not.

8. What is the meaning of sudo?

Answer: sudo is an abbreviation of "super user do" and is a Linux command that allows programs to be executed as a super user (aka root user) or another user.

9. What is the meaning of su?

Answer: 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?

Answer: For gaining administrator or root privileges on current account.

11. Why we use su?

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

12. How to create a user account?

Answer: Use "sudo adduser 'username'" command.

13. How to delete a user?

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

14. How to login into a user account?

Answer Use "sudo login 'username'" command.

15. How to logout from a user account?

Answer: Use 'logout' command.

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

Answer: Two.

17. How to exit from root?

Answer: Use 'exit' command.

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

Answer: Create new user with the specified username.

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

Answer: Delete user by the specified username.

20. What is the meaning of sudo su?

Answer: Switch to root user with all the privileges.