popen4 - get exit status

[Dave Angel]

On 08/27/2012 06:39 PM, Tim Johnson wrote:
> In bash I do the following:
> linus:journal tim$ /home/AKMLS/cgi-bin/perl/processJournal-Photo.pl hiccup
> -bash: /home/AKMLS/cgi-bin/perl/processJournal-Photo.pl: No such file or directory
> linus:journal tim$ echo $?
> 127
>
> In python, use os.popen4 I do the following:
>>>> fin,fout = os.popen4('/home/AKMLS/cgi-bin/perl/processJournal-Photo.pl hiccup;echo $?')
>>>> results = fout.readlines()
>>>> results
> ['/bin/sh: /home/AKMLS/cgi-bin/perl/processJournal-Photo.pl: No such file or directory\n', '127\n']
>
> Well, I got the exit code as the last item in the results, but I'm wondering if
> there is a better way. From help(os) - I don't find any variables dedicated to
> holding exit status.

According to:
    http://docs.python.org/library/popen2.html
<http://docs.python.org/library/popen2.html>

" The only way to retrieve the return codes for the child processes is
by using the poll() or wait() methods on the Popen3
<http://docs.python.org/library/popen2.html#popen2.Popen3> and Popen4
<http://docs.python.org/library/popen2.html#popen2.Popen4> classes;
these are only available on Unix. This information is not available when
using the popen2()
<http://docs.python.org/library/popen2.html#module-popen2>, popen3()
<http://docs.python.org/library/popen2.html#popen2.popen3>, and popen4()
<http://docs.python.org/library/popen2.html#popen2.popen4> functions,...."

However, unless you're using an old version of Python (2.5 or below),
you should be using the subprocess module.




-- 

DaveA