appsettings.json ⇄ environment variables

Microsoft’s configuration documentation: “In environment variables, a colon separator doesn’t work on all platforms. A double underscore (__) is supported by all platforms and is automatically converted into a colon (:) when the configuration is read by the app.”

The index is another part of the name: Cors:Origins:0 becomes Cors__Origins__0. Microsoft’s documentation: “the array index should be treated as an additional element name in the path.”

The JSON provider stores every value as a string, and it writes JSON booleans as True and False. Numbers keep their exact JSON text. This page copies what the provider does, checked against Microsoft.Extensions.Configuration.Json.

The configuration system reads them, but bash can’t export a name containing a dot (bash names allow only letters, digits and underscores). The bash output marks those lines so you can set them another way, or rename the key.

If you call AddEnvironmentVariables("MYAPP_"), only variables starting with MYAPP_ are read, with the prefix removed. Put the same prefix here.