How to hide output of subprocess in Python 2 7

Question

I m using eSpeak on Ubuntu and have a Python 2 7 script that prints and speaks a message   import subprocess text    Hello World   print text subprocess call   espeak   text     eSpeak produces the desired sounds  but clutters the shell with some errors  ALSA lib     no socket connect  so i cannot easily read what was printed earlier  Exit code is 0    Unfortunately there is no documented option to turn off its verbosity  so I m looking for a way to only visually silence it and keep the open shell clean for further interaction   How can I do this

User · Answer

Here s a more portable version  just for fun  it is not necessary in your case       usr bin env python   - - coding  utf-8 - - from subprocess import Popen  PIPE  STDOUT  try      from subprocess import DEVNULL   py3k except ImportError      import os     DEVNULL   open os devnull   wb    text   u Ren   Descartes  p   Popen   espeak    -b    1    stdin PIPE  stdout DEVNULL  stderr STDOUT  p communicate text encode  utf-8    assert p returncode    0   use appropriate for your program error handling here

User · Answer

Use subprocess check output  new in python 2 7    It will suppress stdout and raise an exception if the command fails    It actually returns the contents of stdout  so you can use that later in your program if you want    Example   import subprocess try      subprocess check output   espeak   text   except subprocess CalledProcessError        Do something   You can also suppress stderr with       subprocess check output   espeak   text   stderr subprocess STDOUT    For earlier than 2 7  use  import os import subprocess with open os devnull   w    as FNULL      try          subprocess  check call   espeak   text   stdout FNULL      except subprocess CalledProcessError            Do something   Here  you can suppress stderr with           subprocess  check call   espeak   text   stdout FNULL  stderr FNULL

User · Answer

Redirect the output to DEVNULL  import os import subprocess  FNULL   open os devnull   w   retcode   subprocess call   echo    foo         stdout FNULL       stderr subprocess STDOUT   It is effectively the same as running this shell command  retcode   os system  quot echo  foo   amp  gt   dev null quot    Update  This answer applies to the original question relating to python 2 7  As of python  gt   3 3 an official subprocess DEVNULL symbol was added  retcode   subprocess call   echo    foo         stdout subprocess DEVNULL       stderr subprocess STDOUT

User · Answer

As of Python3 you no longer need to open devnull and can call subprocess DEVNULL   Your code would be updated as such   import subprocess text    Hello World   print text  subprocess call   espeak   text   stderr subprocess DEVNULL

User · Answer

Why not use commands getoutput   instead   import commands  text    Mario Balotelli   output    espeak   s     text print text a   commands getoutput output

[python] How to hide output of subprocess in Python 2.7

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