Implement cat

You should already be familiar with the cat command line tool.

Your task is to implement your own version of cat.

It must act the same as cat would, if run from the directory containing this README.md file, for the following command lines:

• cat sample-files/1.txt
• cat -n sample-files/1.txt
• cat sample-files/*.txt
• cat -n sample-files/*.txt
• cat -b sample-files/3.txt

Matching any additional behaviours or flags are optional stretch goals.

We recommend you start off supporting no flags, then add support for -n, then add support for -b.