New Person Added to the Forum

Hello,

I'm brand new to this forum. I am working on my first Bash shell script. We were given an exercise to get ready for the real assignment. I could use some help.

The exercise is to "set two variables (i. e., file1 & file2) on the command line to the paths of the text files. We are to create a shell script that does the following:
"if either variable does not have a value, output a message and stop. file1=${file1:?must set file1} & file2=:?must set file2} is what I've composed so far.

The output : "There are ___________ lines total in the files. ________has __________% (files) as many __________. "

#I did this part. I typed in lines of text into both files. We are to use quota, echo, run tests, and edit/compose the script in the Vi editor.

The process of doing this is a bit confusing to me.
First I set variables.
Second, I create paths w/text.
Third, I export files.
Fourth, run tests.
Fifth name script files in Vi.

What does $SHELL do?

Can someone model this entire process for me so that I can get a handle how to accomplish the basics of using vi and writing a script?

I would be greatful!

Sincerely,

William Carpenter

William - please read the rules