Q:

What will be the effect if I use the same python virtualenv in different OS system

What will be the effect if I use the same python virtualenv in different OS system?

If not possible, why?

Its said that what can confirm if the virtualenv can used in the os system?

A:

the purpose of virtualenv is to separate your python environment, so one virtualenv may have, let's say Django version 1.11 with Python 3, while another virtualenv have django 1.10 with python 2.7 , Using the same python virtualenv in different OS system is doable, pip inside the virtualenv will handle the libraries while the python will handle OS differences when you install python 2.7 or python 3.0 inside the virtualenv.
One of the example use of these two virtualenv is let's say your Nginx Server is using different python environment for each domain (one nginx server can handle many domains).

