Right now I'm using virtualenv and just switching over to Pipenv. Today in virtualenv I load in different environment variables and settings depending on whether I'm in development, production, or testingby setting DJANGO_SETTINGS_MODULE to myproject.settings.development, myproject.settings.production, and myproject.settings.testing.
I'm aware that I can set an .env file, but how can I have multiple versions of that .env file?
You should create different .env files with different prefixes depending on the environment, such as production.env or testing.env. With pipenv, you can use the PIPENV_DONT_LOAD_ENV=1 environment variable to prevent pipenv shell from automatically exporting the .env file and combine this with export $(cat .env | xargs).
export $(cat production.env | xargs) && PIPENV_DONT_LOAD_ENV=1 pipenv shell would configure your environment variables for production and then start a shell in the virtual environment.