* COMMENT -*- mode: org -*-
#+Date: 2017-02-23
Time-stamp: <2017-02-23>

** When a python program support reading from stdin, it can accept input from
stdin redirect or shell pipes. For example:

    python main.py < /path/to/foo.txt
    cat /path/to/foo.txt | python main.py

sys.stdin is a file like object, usually you process line by line via
readline() call. You can also read it all though.