Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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 >> temp.txt

If I kill the process no data is logged.

share|improve this question
I wonder that it works that way -- but the easiest thing to come up with would be turning your function into a separate shell script to be called instead. Would that be an acceptable solution? – Izzy Jul 20 '12 at 19:55
It would be extremely difficult to do this. Looking for a simpler solution – Matt Stokes Jul 20 '12 at 20:15
up vote 2 down vote accepted

Now that you mention it is not a shell function, but a python function in a python script: That explains some, and here comes your answer:

printing - How to flush output of Python print? - Stack Overflow

You need to put that inside your python function's loop: sys.stdout.flush() -- and of course you need to import sys before (or from sys import ... if you only need a part of it).

share|improve this answer
Works perfectly thank you! – Matt Stokes Jul 23 '12 at 14:31

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.