Reading from sys.stdin reads the whole file in
Peter Otten
__peter__ at web.de
Wed Aug 27 03:42:40 EDT 2014
Steven D'Aprano wrote:
> I'm trying to read from stdin. Here I simulate a process that slowly
> outputs data to stdout:
>
> steve at runes:~$ cat out.py
> import time
>
> print "Hello..."
> time.sleep(10)
> print "World!"
> time.sleep(10)
> print "Goodbye!"
In addition to what already has been said: you can switch off output
buffering of stdout/stderr with
python -u out.py
or by setting the PYTHONUNBUFFERED environment variable.
You still need the readline trick to get unbuffered input. Quoting the man-
page:
"""
-u Force stdin, stdout and stderr to be totally unbuffered. On
systems where it matters, also put stdin, stdout and stderr in
binary mode. Note that there is internal buffering in xread‐
lines(), readlines() and file-object iterators ("for line in
sys.stdin") which is not influenced by this option. To work
around this, you will want to use "sys.stdin.readline()"
inside a "while 1:" loop.
"""
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