Retrieving the output of subprocess.call() [duplicate]
If you have Python version >= 2.7, you can use subprocess.check_output which basically does exactly what you want (it returns standard output as string).
Simple example (linux version, see note):
import subprocessprint subprocess.check_output(["ping", "-c", "1", "18.104.22.168"])
Note that the ping command is using linux notation (
-c for count). If you try this on Windows remember to change it to
-n for same result.
As commented below you can find a more detailed explanation in this other answer.
subprocess.call() should only be redirected to files.
You should use
subprocess.Popen() instead. Then you can pass
subprocess.PIPE for the stderr, stdout, and/or stdin parameters and read from the pipes by using the
from subprocess import Popen, PIPEp = Popen(['program', 'arg1'], stdin=PIPE, stdout=PIPE, stderr=PIPE)output, err = p.communicate(b"input data that is passed to subprocess' stdin")rc = p.returncode
The reasoning is that the file-like object used by
subprocess.call() must have a real file descriptor, and thus implement the
fileno() method. Just using any file-like object won't do the trick.
See here for more info.
For python 3.5+ it is recommended that you use the run function from the subprocess module. This returns a
CompletedProcess object, from which you can easily obtain the output as well as return code.
from subprocess import PIPE, runcommand = ['echo', 'hello']result = run(command, stdout=PIPE, stderr=PIPE, universal_newlines=True)print(result.returncode, result.stdout, result.stderr)