Python: Catching the output from subprocess.call with stdout

Question

So im trying to save the output from my subprocess.call but I keep getting the following error: AttributeError: 'int' object has no attribute 'communicate'

Code is as follows:

p2 = subprocess.call(['./test.out', 'new_file.mfj', 'delete1.out'], stdout = PIPE)
output = p2.communicate[0]

Answer 1

You're looking for subprocess.Popen() instead of call().

You also need to change it to p2.communicate()[0].

Answer 2

That's because subprocess.call returns an int:

subprocess.call(args, *, stdin=None, stdout=None, stderr=None, shell=False)

    Run the command described by args. Wait for command to complete, then return the returncode attribute.

It looks like you want subprocess.Popen().

Here's a typical piece of code I have to do this:

p = Popen(cmd, stdout=PIPE, stderr=PIPE, bufsize=256*1024*1024)
output, errors = p.communicate()
if p.returncode:
    raise Exception(errors)
else:
    # Print stdout from cmd call
    print output