If I run the following in one tty: nc -l localhost 9000 | /tmp/z ...where /tmp/z has just: #!/usr/bin/python3
import sys for line in sys.stdin.buffer: print(line) And then run the following in another tty on the same computer: while read line; do echo $line; sleep 1; done < /etc/passwd | nc localhost 9000 ...then everything acts line buffered, or perhaps even character buffered (the two are pretty indistinguishable in this test). What I see is my /etc/passwd file popping out of the nc -l side, one line at a time, each line one second apart. I suppose this suggests that it's the client that's sending TCP data that is buffering. That, or we're using two different versions of netcat (there are at least two available). -- https://mail.python.org/mailman/listinfo/python-list