subprocess.check_output return code

python subprocess
Juicy picture Juicy · May 2, 2014 · Viewed 83.3k times · Source

I am using:

grepOut = subprocess.check_output("grep " + search + " tmp", shell=True)

To run a terminal command, I know that I can use a try/except to catch the error but how can I get the value of the error code?

I found this on the official documentation:

 exception subprocess.CalledProcessError

    Exception raised when a process run by check_call() or check_output() returns a non-zero exit status.

    returncode

        Exit status of the child process.

But there are no examples given and Google was of no help.

Answer

DanGar picture DanGar · May 2, 2014

You can get the error code and results from the exception that is raised.

This can be done through the fields returncode and output.

For example:

import subprocess

try:
   grepOut = subprocess.check_output("grep " + "test" + " tmp", shell=True)                       
except subprocess.CalledProcessError as grepexc:                                                                                                   
    print "error code", grepexc.returncode, grepexc.output

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