How to use PHPCS and PHPCBF with a single WordPress file

PHPCS and PHPCBF are two well-know PHP scripts used in the PHP development to (PHPCS) detect violations of a defined coding standard, and (PHPCBF) to automatically correct coding standard violations. 

I usually use both with composer in my WordPress projects, adding them as dependency in the composer.json file.

But sometimes I need to check some individual PHP file without adding PHPCS and PHPCBF as dependency. In this post, I am going to explain how I do this.