read variable value from bash executable-CodePudding

I have a script:

x.sh:

#!/bin/bash
echo nir

config.sh:

#!/bin/bash
x=$(/home/nir/x.sh)

script.py:

#!/usr/bin/env python3
#execute config.sh and read x into y
print(y)

terminal:

$ ] ./x.sh
nir
$ ] . ./config.sh
$ ] echo $x
nir
$ ] ./script.py
nir

I want to use config.sh in a python script to execute it and then read the value in x. Not sure how to do it.

CodePudding user response：

Since config.sh is not showing output, you need another command for showing the value of x. Any shell variable set in a subprocess is lost when the subprocess is finished, so you can not use two calls to subprocess.
The same problem is valid for config.sh: the variables are lost when the script is finished. You need to source the file with a . for the variable to be remembered in the subprocess environment. Before finishing the subcommand, you must echo the value.
All steps together:

#!/usr/bin/env python3
import subprocess

cmd = '''
. /home/nir/config.sh
echo "$x"
'''

# returns output as byte string
returned_output = subprocess.check_output(cmd, shell=True)

# using decode() function to convert byte string to string
y=returned_output.decode("utf-8")
print(y)