IPC w/ bash | python

README.md

EXTREMELY crude example of using anonymous pipes to communicate between a bash and python script running in parallel (NOTE: Only tested in default OS X Mavericks shell)

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To run it yourself: ./app1.sh | python app2.py

app1.sh

#!/bin/bash - 

set -o nounset # Treat unset variables as an error


# doing some stuff and simulating processing time by sleeping
echo 'Initial setup'
sleep 2

# now we trigger python script
echo 'APP2_GO'

# pretending to do other stuff
echo 'super cool processing is happening right now!'
sleep 2

# now we tell python script we're done
echo 'APP2_DONE'

app2.py

#!/usr/bin/python

import sys
import time

k = 0
try:
    buff = ''
    while True:
        buff += sys.stdin.read(1)

        if buff.endswith('\n'):
            # output line of text received from app1.sh
            print "app1 msg", (k, buff[:-1])

            # handle text triggers below
            if buff[:-1] == "APP2_GO":
                print "Python app starts doing radical stuff now!"

            elif buff[:-1] == "APP2_DONE":
                print "Python app now knows the shell script is done!"
                break

            buff = ''
            k = k + 1

except KeyboardInterrupt:
   sys.stdout.flush()
   pass