How to run a bash script in python and use the variables that where defined in that script

Question

I'm running a bash script inside of a Python script, and I need to use the variables that were defined inside of the bash script, in the Python script.

For some context, here is the bash script:

#!/bin/bash
updates=$(/usr/lib/update-notifier/apt-check 2>&1)
all=${updates%";"*}
security=${updates#*";"}

Here is how I am calling it in the Python script:

import subprocess
subprocess.call(["/usr/bin/checkupdates"])

I want to use the variables that were defined in that bash script ('all' and 'security') in this SQL update statement (which is part of the Python script):

cursor.execute("update dbo.updates_preprod set updates_available = ?, securityupdates_available = ? where hostname = ?",(all, security , socket.gethostname()))
cnxn.commit()

Is it possible to do this? If not, could I run 2 separate scripts (each script would echo one of the variables) and grab the stdout of each script and define it as a variable in Python?

Thanks in advance!

bash has to display values (using echo) and then Python can get this text with values and use it in SQL query. But I would display updates to get and change it in Python. I would even run /usr/lib/update-notifier/apt-check 2>&1 directly with subprocess. — furas
– furas, Commented Apr 28, 2019 at 1:33
instead of call() you should use output = subprocess.check_output(...) or output = subprocess.run(...).stdout. More in documentation: subprocess — furas
– furas, Commented Apr 28, 2019 at 1:41
Mixing languages is never a good design choice, probably better to rewrite the bash script in python. i.e. why not call /usr/lib/update-notifier/apt-check from python? — cdarke
– cdarke, Commented Apr 28, 2019 at 9:32

Trevor Ludgate · Accepted Answer · 2019-04-29 22:58:33Z

1

In the end it was much easier to call that command directly from the Python script.

output = subprocess.check_output("usr/lib/update-notifier/apt-check", shell=True) all,sec = output.decode().split(';')

Thanks to @cdarke and @furas for the suggestion.

edited Apr 29, 2019 at 22:58

answered Apr 29, 2019 at 18:14

Trevor Ludgate

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cdarke Over a year ago

@furas also suggested that

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