Python3 - Returning output of bash script to variable

Question

I'm playing around with what should be a simple script. I've goa bash script one line that just runs an API call to a server I have. I've got a py3 script that calls that bash script in a function and returns the output.

I'm then setting a variable equal to the function, and finally printing that variable.

For some reason even though im not directly calling the function (I guess I am when im declaring my variable) it's running the function anyway, and my variable's value is set to 0.

I've tried it a couple different ways and set it up similar to how some of the posts on here have said but I just dont understand why it's doing this.

#!/usr/bin/env python3

import subprocess


def api_call():
    return subprocess.call("/home/gposcl1/PyNetBox/api_GET.sh")
    
print("")
print("")
print("")

api_call_result = api_call()

print("")
print("")
print("")

print(api_call_result)

This is the output im getting. I've changed the output of the API call as it's rather unipmortant to the question and contains sensitive data:

$  
$ ./var1.py            



{"count":3,"next":null,"previous":null,"results":[{"id":31689,"url":,"role":null,"is_pool":false,"description":"1234_lower","tags":[],"custom_fields":{},"created":"2021-02-05","last_updated":"2021-02-05T06:20:16.733088Z"}]}


0
$

check this post https://stackoverflow.com/questions/4760215/running-shell-command-and-capturing-the-output — paulogil2010, Apr 09 '21 at 21:44

score 1 · Answer 1 · answered Apr 09 '21 at 21:52

1

If you use run instead of call, you can set capture_output to True and then retrieve stdout:

def api_call():
    r = subprocess.run("/home/gposcl1/PyNetBox/api_GET.sh", capture_output=True)
    return r.stdout.decode()

answered Apr 09 '21 at 21:52

joao

2,220
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I'm on py3.6 so this wont work for me but maybe my admin will upgrade me. – Sean Liles Apr 09 '21 at 21:57
Are you sure ? Documentation for 3.6 says _"The run() function was added in Python 3.5;"_. – joao Apr 09 '21 at 21:58
1

Oh, I see, it's the `capture_output` that's missing – joao Apr 09 '21 at 21:59
Tyr replacing `capture_output=True` with `stdout=subprocess.PIPE` – joao Apr 09 '21 at 22:02

score -1 · Answer 2 · answered Apr 09 '21 at 22:01

#!/usr/bin/env python3

import subprocess


def api_call():
    r = subprocess.run("/home/gposcl1/PyNetBox/api_GET.sh", stdout=subprocess.PIPE)
    return r.stdout


print("")
print("")
print("")

api_call_result = api_call()

print("")
print("")
print("")

print(api_call_result)

Python3 - Returning output of bash script to variable

2 Answers2