Overriding configuration with environment variables in typesafe config

Question

Using typesafe config, how do I override the reference configuration with an environment variable? For example, lets say I have the following configuration:

foo: "bar"

I want it to be overriden with the environment variable FOO if one exists.

Answer 1

If I correctly understood your question, the answer is here. You can do

foo: "bar"
foo: ${?FOO}