Turn off buffering

Question

Where is the buffer in this following ... and how do I turn it off?

I am writing out to stdout in a python program like so:

for line in sys.stdin:
           


        

Answer 1

file.readlines() and for line in file have internal buffering which is not affected by -u option (see -u option note). Use

while True:
   l=sys.stdin.readline()
   sys.stdout.write(l)

instead.

By the way, sys.stdout is line-buffered by default if it points to terminal and sys.stderr is unbuffered (see stdio buffering).