/prog/ Challenge: Micro$oft Excel 2018

Write a command line tool that takes in a CSV file, overwrites all the data of a given column by a given value, and outputs the results into a new CSV file.

More specifically, this command line tool should accept the following arguments:

1. the filename of a CSV file,
2. the name of the column to overwrite in that file,
3. the string that will be used as a replacement for that column,
4. the filename where the output will be written.