setting environment int variable in Linux for use in a while loop in python but loop doesn't stop -

i'm controlling led on raspberry pi 2 python. want led go on x seconds. when set environment variable in linux. example, export t=5. led goes on won't go off.

if set variable in python script works fine.

i'm setting environment variable in linux so:

export t=5 sudo python test.py 

and getting in python so:

 #!/usr/bin/env python      import rpi.gpio gpio     import time     import os       gpio.setmode(gpio.board)      gpio.setup(11,gpio.in, pull_up_down=gpio.pud_down)      gpio.setup(12,gpio.out)      gpio.output(12,0)      s = 0      t = os.environ.get('t')      while s <= t:             if (gpio.input(11) == 1):                              gpio.output(12, 1)                              time.sleep(0.1)                              s += 0.1             else:                     gpio.output(12, 0)      gpio.output(12, 0) 

the values of environment variables — , values of os.environ — stored strings. thus, need convert t number in order comparison s want:

t = int(os.environ.get('t'))