Here is what I tried:

Setup venv and install jupyter lab

python3 -m venv venv
source venv/bin/activate
pip install --upgrade pip
pip install jupyterlab
export FOO="bar"

run Jupyter Lab:

./venv/bin/jupyter lab

inside the notebook:

import os
print(os.getenv("FOO"))

returns: bar

perfect.

Now, I want to add another env var. So in another terminal:

source venv/bin/activate
export FOOX="bar"

and

import os
print(os.getenv("FOOX"))

returns None

Why?

I tried restarting the kernel.
I tried restarting jupyter lab.

There must be something I don’t understand about env vars. Using another terminal may be the issue?