Write a command line program that takes several CSV files as arguments. Each CSV file (found in the fixtures directory of this repo) will have the same columns. Your script should output a new CSV file to stdout that contains the rows from each of the inputs along with an additional column that has the filename from which the row came (only the file's basename, not the entire path). Use filename as the header for the additional column.

• You should use coding best practices. Your code should be re-usable and extensible.
• Your code should be testable by a CI/CD process.
• Unit tests should be included.

This example is provided as one of the ways your code should run. It should also be able to handle more than two inputs, inputs with different columns, and very large (> 2GB) files gracefully.

$ ./csv-combiner.php ./fixtures/accessories.csv ./fixtures/clothing.csv > combined.csv

Given two input files named clothing.csv and accessories.csv.

Your script would output