Remember command line variables in python

Question

I want to make the command line run in python.

For Example:

import subprocess

subprocess.call('set /A x = 5', shell=True)  
subprocess.call('echo %x%', shell=True)  

I'd like that i remember the value 5 that x was set to. But instead it echos just %x% as a string.

Answer 1

Using a subprocess means very concretely that you run another process. The process in which the variable was set will no longer exist when control returns from the subprocess back to Python.

Try

import os
import subprocess

env = os.environ.copy()
env['x'] = '5'
subprocess.check_call(
    'echo %x%',
    shell=True,
    env=env)

Notice also the switch to check_call - it probably doesn't matter a great deal here, but you should usually check for subprocess failures.