Question

My issue is that I have a function call it function1 which runs indefinitely. The function itself echo’s “hello” every 1 second. Using the command:

function1 >> temp.txt

Every 1 second if I am to view the file temp.txt I should see a new line with “hello”. However what’s happening is that the function doesn’t write to the file until its finished running. Therefore if I am to kill the function nothing will be written. Does anyone know of something I can do in this situation that will basically dynamically update temp.txt?

I have a python script set up the following way:

while [1>0]:
   print "hello"
   time.sleep(1)

Therefore this will always be running. Now I call this in a bash script

python pythonscript.py >> temp.txt

If I kill the process no data is logged.

Answer 1

You are going to want to flush the buffer after each print.

import time
import sys

while [1>0]:
    print "hello"
    sys.stdout.flush()
    time.sleep(1)

This will also work on other operating systems.