Set environment variables in a python script and use them in a chained call [duplicate]

Question

I would like to set a couple of environment variables in a Python script, then use said environment variables in a chained call.

For example, a python script called set_env.py:

os.environ["MY_VAR"] = "cool value"

And then in bash

python ./set_env.py && echo "$MY_VAR"

Is such a thing possible?

I've tried to use the os.environ, os.system using export MY_VAR=..., but none of them seem to work.

Answer 1

Since python runs in a child process of the shell it can't directly alter the shell's environment variables. However, your python script can output proper shell commands that can be evaluated in the shell.

$ python ./set_env.py
MY_VAR="x y z";MY_VAR2="a b c"

Then use the output of your python script like this:

$ eval "$(python ./set_env.py)" && echo "$MY_VAR"
x y z