Compare csv files

Hi

Basically what I'm looking for is something that compares line by line csv files which have the exact same names and have anywhere from 1 to 150 columns and 5000 rows.

These files are currently located in two folders, one called PRE and the other POST.
What I'm looking for is something that will save the results into a separate file called RESULTS

Here is what I'm looking for the RESULTS file to display:

(1) Any entries that DO NOT exactly match, and to SHOW the PRE entry and the POST entry displayed in RED

(2) Any files that EXIST in the POST and DON'T exist in the PRE, displaying the entries too.

Cheers
Danny//