Please answer two questions from the ones listed below and respond to two threads of your classmates.

What is a shell?

What is the difference between how executable programs are run by a Linux shell and a DOS environment?

What is the difference between how a Linux shell recognizes the path to executable programs and how a DOS environment recognizes the path?

What common commands are used to navigate through shells?

What types of items can you use the Tab key to complete once you start typing the entities' name?

What does the tilde symbol $($~$)$ in the prompt indicate?