Using subprocess in python 3

Question

I was using the subprocess module to run the shell command in python 3. Here is my code ``` import subprocess filename = "somename.py" # in practical i'm using a real file, this is just for example subprocess.call("pep8 %s" % filename, shell=True)) ``` The output for different files is just `0` or `1`. I am quite new to python 3. Using this in 2.7 gives me the desired output, but here i am not able to figure it out. This is the output i get in python 2.7 (for a file named - `anu.py` ) - ``` anu.py:2:1: W191 indentation contains tabs anu.py:3:1: W191 indentation contains tabs anu.py:3:7: E228 missing whitespace around modulo operator anu.py:4:1: W191 indentation contains tabs anu.py:5:1: W191 indentation contains tabs anu.py:6:1: W191 indentation contains tabs anu.py:7:1: W191 indentation contains tabs anu.py:7:9: E231 missing whitespace after ',' anu.py:8:1: W191 indentation contains tabs anu.py:9:1: W191 indentation contains tabs 1 ``` Please help me guys. Thanks Update: I tried usin…

Accepted Answer

`subprocess.call` only returns the exit code of the process it ran. Normally I'd recommend using `subprocess.check_output`, which will return the actual output of the subprocess. However, in your particular case, `pep8` will return a non-zero exit code in some cases, which will make `check_output` raise an exception. You can catch the exception and extract the output attribute from it:

```
try:
    output = subprocess.check_output(['pep8', 'anu.py'])
except subprocess.CalledProcessError as e:
    output = e.output
```

Or just use `subprocess.Popen` directly:

```
p = subprocess.Popen(['pep8', 'anu.py'], stdout=subprocess.PIPE)
(output, _) = p.communicate()
```

Note that the `call` behavior hasn't changed between Python 2.x and Python 3.x. The difference in behavior you're seeing might be because you're running Python 2.7 in an interactive prompt, but running the Python 3 version as an actual script. Using `subprocess.call` in the interactive prompt will still end up printing the output of the call, even though it's not actually being returned by the function.

Using subprocess in python 3

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