A simple Python script to turn on or off an output for a PiFace Digital board

heater.py

#!/usr/bin/python

# By Duncan Westland
# Programme to control a heater via command line switches.
# Uses a Raspberry Pi

import sys
import pifacedigitalio

piFace = pifacedigitalio.PiFaceDigital() #creat piface digital object

def printUsage():
    print
    print "-n to turn on"
    print "-f to turn off"
    print "-h or --help prints this message"
    print

def turnOn():
        piFace.output_pins[2].turn_on() #turn OC pin 2 on

def turnOff():
        piFace.output_pins[2].turn_off() #turn OC pin 2 off


def main():
    if (len(sys.argv)<2):
        printUsage()
    elif sys.argv[1]=="-n":
        print "turning on"
        turnOn()
    elif sys.argv[1]=="-f":
        print "turning off"
        turnOff()
    else:
        printUsage()
    sys.exit(2)
        
if __name__=="__main__":
    main()