Using virtual environments is common when working with Python development. We will begin by understanding what a Python virtual environment is, its benefits, and how to create, activate, and delete the Python virtual environment. This guide offers a hands-on tutorial about Python’s virtual environment. Besides, a virtual environment is the best way to separate the dependencies when you have different projects requiring different versions of the same package. These lines are executed when you activate the virtual environment.When working on a Python project, creating a virtual environment for the project is recommended, such that you isolate the project requirements from the system.

At the end of the script add lines, where you define the 'new value of the ENV_VARIABLE'.

They restore the previous value of the ENV_VARIABLE. These lines are executed when you deactivate the virtual environment.

Update the body of the deactivate function.

Open the activate script in any text editor (e.g vim).restores the previous value of the environment variable on deactivation.sets or updates an environment variable on activation.Setup: $ cat $VIRTUAL_ENV/bin/postactivateĬoncerning the standard venv package, here is a solution that: So if that is at all probable you could record the previous value somewhere temporary then read it back in on deactivate. Remember that if using this for environment variables that might already be set in your environment then the unset will result in them being completely unset on leaving the virtualenv. # This hook is run before this virtualenv is deactivated. To clean up symmetrically you can add to $VIRTUAL_ENV/bin/predeactivate. When you deactivate the virtualenv, the environment variable will persist. Remember that this wont clean up after itself. You could even automate the creation of the symlinks each time you use mkvirtualenv. env/postactivate $VIRTUAL_ENV/bin/postactivate

If you want to keep this configuration in your project directory, simply create a symlink from your project directory to $VIRTUAL_ENV/bin/postactivate. # This hook is run after this virtualenv is activated. In case you're using virtualenvwrapper (I highly recommend doing so), you can define different hooks (preactivate, postactivate, predeactivate, postdeactivate) using the scripts with the same names in $VIRTUAL_ENV/bin/.

Python3 virtualenv