builing a long variable-length command-pipeline

[wavic]

You read from standard out and write to standard in, right?

#!/usr/bin/env python3

import sys

if len(sys.argv) > 1:
    pipe_in = sys.stdin.read().strip()
    sys.stdout.write('{} {} \n'.format(pipe_in, ' '.join(sys.argv[1:])))
else:
    pipe_in = sys.stdin.read().strip()
    sys.stdout.write('{} \n'.format(pipe_in))

You have to be careful with the quotes. If you put double quotes for the strings you get EOL error because of the bash quoting. I've needed some time to get it during this example. I have to test it before to publish  

victor@jerry:/tmp$ echo hello | ./piped.py world
hello world

victor@jerry:/tmp$ echo hello | ./piped.py
hello

victor@jerry:/tmp$ echo hello | ./piped.py | ./piped.py
hello

victor@jerry:/tmp$ echo hello | ./piped.py beautiful | ./piped.py world
hello beautiful world

victor@jerry:/tmp$ echo hello | ./piped.py beautiful | ./piped.py beautiful world
hello beautiful beautiful world