Ubuntu :: Grep Script That Finds Searched Keyword

I need to write a script that can search up to 3 parameters and find all files containing those words. then display them and the amount of hits it got.if the first parameter exists, then we can assume we are looking for the word supplied.if the second parameter exists, then we are looking for files with both keywords.if third parameter exists test the second parameter for the values ('and', 'or', '-v') and search accordingly. These are the only values accepted as the the second one when 3 parameters are present.

lastly, if there are zero or more than three parameters echo as an error and when 3 parameters have been entered we echo an error when the second parameter is not one of the following: 'and', 'or', '-v'.