.env, in the working
directory of a project, and then set them as environment variables.
.env file
in the current working directory (as reported by getwd),
and sets them as environment variables.This happens automatically when the dotenv package is loaded,
so the typical use-case is to just put a `library(dotenv)` code at the
beginning of your R script.
Alternatively a dotenv::load_dot_env() call can be used
to load variables from arbitrary files.
The format of the .env file is also a valid unix shell
file format, so e.g. in bash the environment variables
can also be set by running source .env.
See load_dot_env for the exact file format.