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Date: Thu, 18 Oct 2012 14:05:58 +0100
Subject: Watching output and put back in background
From: andrea crotti <andrea.crotti.0@gmail.com>
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Xref: csiph.com comp.lang.python:31632

In one process I need to run many quite weird shell commands that take a
long time, possibly in parallel.

Now the problem is that I need to catpure the initial standard error of
the command and then I can go on with the second one, but how can I do
that?

It should be something like

Popen(long_command..)

- first line output
- second line
- interesting line

.. more things ..

But if I just do

out, err = proc.communicate()

it will hang there until the end, right?

Maybe a solution would be to redirect the stderr to file and watch that
instead..

Or otherwise I could use a thread for each shell command, but I would
like to avoid head-aches with possible race-conditions..

Ideas?