How to read a file from command line using Python?

In order to read a file form command line using Python, the script you want to use for it needs to accept a CLI argument. For example, say you want to write a cat command in python(a command that dumps all file content on the terminal). In order to do that, you could simply write a program:

import sys
with open(sys.argv[1], 'r') as f:
    contents = f.read()
print contents

If you save this file as cat.py and run it using:

$ python cat.py my_file.txt

This will take the my_file.txt and pass it to cat.py as a CLI argument in variable argv[1](second command line argument) which we can use to get the file and its contents.