Suppressing output in python subprocess call

python, stdout, subprocess

Solution

You can use the `stdout=` and `stderr=` parameters to `subprocess.call()` to direct `stdout` or `stderr` to a file descriptor of your choice. So maybe something like this:

import os

devnull = open(os.devnull, 'w')
subprocess.call(shlex.split(
    '/usr/local/itms/bin/iTMSTransporter -m lookupMetadata '
    '-apple_id %s -destination %s' % (self,apple_id, self.destination)),
  stdout=devnull, stderr=devnull)

Using `subprocess.PIPE`, if you're not reading from the pipe, could cause your program to block if it generates a lot of output.

Update

As @yanlend mentions in a comment, newer (3.x) versions of Python include `subprocess.DEVNULL` to solve this problem in a more convenient and portable fashion. In that case, the code would look like:

subprocess.call(shlex.split(
    '/usr/local/itms/bin/iTMSTransporter -m lookupMetadata '
    '-apple_id %s -destination %s' % (self,apple_id, self.destination)),
  stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)

Problem

For the following command: ``` subprocess.call(shlex.split( """/usr/local/itms/bin/iTMSTransporter -m lookupMetadata -apple_id %s -destination %s"""%(self.apple_id, self.destination)) ``` It prints the entire output into the Terminal window. How would I suppress ALL output here? I tried doing `subprocess.call(shlex.split(<command> > /dev/null 2&1`)), but it didn't produce the required results. How would I do this here?

Original source

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