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Re: os.system and subprocess odd behavior

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On 17 December 2012 16:39, py_genetic <conor.robinson@gmail.com> wrote:
> Thanks for verifying this for me Steven.  I'm glad you are seeing it work.  It's really the strangest thing.
>
> The issue seems to be with the " > outfile.txt" portion of the command.
>
> The actual command is running a query on a verticalDB and dumping the result.  The EXACT command run from the command line runs just fine.
>
> Even if I use the simple cat command to and out file as just a simple test case...  The file is created with zero bytes (see below)... but its as if python moves on or gets an 0 exit code after the first part of the cmd is executed  and no data is written.
>
> -rw-r--r-- 1 root root        0 Dec 14 15:33 QUAD_12142012203251.TXT
>
> Any thoughts as to why on my end this may happen?

Because of the root permissions on the file? What happens if you write
to a file that doesn't need privileged access?

Instead of running the "exact command", run the cat commands you
posted (that Steven has confirmed as working) and run them somewhere
in your user directory without root permissions.

Also you may want to use subprocess.check_call as this raises a Python
error if the command returns an error code.


Oscar

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os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-14 10:13 -0800
  Re: os.system and subprocess odd behavior Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-12-14 22:47 +0000
    Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-17 08:39 -0800
      Re: os.system and subprocess odd behavior Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2012-12-17 17:16 +0000
        Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-17 12:56 -0800
          Re: os.system and subprocess odd behavior Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2012-12-18 00:01 +0000
            Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-18 10:26 -0800
              Re: os.system and subprocess odd behavior Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2012-12-18 18:52 +0000
                Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-18 12:52 -0800
                Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-18 12:52 -0800
            Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-18 10:26 -0800
          Re: os.system and subprocess odd behavior Hans Mulder <hansmu@xs4all.nl> - 2012-12-18 23:46 +0100
        Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-17 12:56 -0800
  Re: os.system and subprocess odd behavior Dieter Maurer <dieter@handshake.de> - 2012-12-15 08:12 +0100
    Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-17 08:30 -0800
    Re: os.system and subprocess odd behavior py_genetic <conor.robinson@gmail.com> - 2012-12-17 08:30 -0800
  Re: os.system and subprocess odd behavior photonymous@gmail.com - 2012-12-17 21:10 -0800
    Re: os.system and subprocess odd behavior Hans Mulder <hansmu@xs4all.nl> - 2012-12-18 11:27 +0100
      Re: os.system and subprocess odd behavior Dave Angel <d@davea.name> - 2012-12-18 05:39 -0500
        Re: os.system and subprocess odd behavior Hans Mulder <hansmu@xs4all.nl> - 2012-12-18 12:40 +0100

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