The xkcd is a joke that if you want to do anything in Linux, just put in a sudo.
The blog post is a Makefile content that you will enable you to type it in the terminal with the output as the comic.
What you should try is to create a file named `Makefile`, put in the content in the blog post. Then open the terminal and type `make me a sandwich` then `sudo make me a sandwich` and see the result.