#!/usr/bin/python3
"""Where is root?  A simple pipeline example without the shell.

From <https://docs.python.org/3.7/library/subprocess.html#replacing-shell-pipeline>.

"""
import subprocess, sys

def root():
    p1 = subprocess.Popen(["df"], stdout=subprocess.PIPE)
    p2 = subprocess.Popen(["grep", "/$"], stdin=p1.stdout, stdout=subprocess.PIPE)
    p1.stdout.close()
    return p2.communicate()[0]

if __name__ == '__main__':
    sys.stdout.buffer.write(root())