Simple script for monitoring a subprocess and restart it based on string match

monitor.py

import subprocess
import sys

def start_program(program):
    proc = subprocess.Popen([program], stdout=subprocess.PIPE)
    return proc

def monitor_program(proc, match):
    for line in iter(proc.stdout.readline, ''):  # replace '' with b'' for Python 3
        sys.stdout.write(line)
        if match in line:
            return 'restart'
    return 'shutdown'

def start_and_monitor_program(program, match):
    proc = start_program(program)
    program_status = monitor_program(proc, match)
    return (program_status, proc)

def run(program, match):
    status, proc = start_and_monitor_program(program, match)
    while status is 'restart':
        sys.stdout.write('Restarting program\n')
        proc.kill() 
        status, proc = start_and_monitor_program(program, match)


run('./infinite.sh', '5')