strange subprocess behavior when calling ps

Roger Davis rbd at
Wed Nov 17 05:05:17 CET 2010

Thanks, Chris, you're at least on the right track. I did upgrade from and the python in my shell PATH is /Library/Frameworks/

% python
Python 2.6.6 (r266:84374, Aug 31 2010, 11:00:51)
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin

/usr/bin/python is the Apple-distributed 2.6.1:

% /usr/bin/python
Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin

This still doesn't explain the behavior to me, however. In either case
python is supposed to be forking a child process with a specific
executable (/bin/ps) and a specific argument list (-e) and reading
that command's output lines. Why should those output lines be
different whether I use 2.6.1, 2.6.6 or 8.9.10 for that matter? In
fact, this makes the problem that much worse -- the newer python 2.6.6
is the one producing the incorrect output. Changing the first line of
the script to read


does not help, it still prints out the wrong output whether I do

% ./


% /Library/Frameworks/Python.framework/Versions/2.6/bin/python ./

Any ideas?


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