How to read from stdin or from a file if no data is piped in Python?

Question

I have a CLI script and want it to read data from a file. It should be able to read it in two ways :

• cat data.txt | ./my_script.py
• ./my

Answer 1

Process your non-filename arguments however you'd like, so you wind up with an array of non-option arguments, then pass that array as the parameter to fileinput.input():

import fileinput
for line in fileinput.input(remaining_args):
    process(line)