Can not set an environmental variable by python in ubuntu

Question

I am testing a simple python script to set an environmental variable by os module but it seems it doesn't work, what is wrong with my code or logic?

webcluster4u@ingestion-jenkins-vm:~$ python
Python 2.7.13 (default, Sep 26 2018, 18:42:22)
[GCC 6.3.0 20170516] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.environ['ENV']='ss'
>>> os.environ.get('ENV')
'ss'
>>> exit()
webcluster4u@ingestion-jenkins-vm:~$ echo $ENV
webcluster4u@ingestion-jenkins-vm:~$

Answer 1

There's nothing wrong with your script.

This by design. Your python script runs in a child process which inherits the shell's environment, but does not affect it. Any changes you make to the environment will affect the script's process and it's children if any.

• Mahdi: How to make it work? i.e setting the environmental variable by the python script?
• Yakov Dan: You could export your variables to a bash script and then run it once your script is finished.
• Mahdi: I guess irregardless of python or bash I can not set an environmental variable by scripts due to the point you told here.
• Yakov Dan: Not quite. You can execute a bash script in a bash console. That will change the environment for that console. You can prepare that bash script using python.
• Mahdi: if I run a python script that run that bash, it can not change the environmental variables!, otherwise can you give me a sample code?