So now you need to wrap all your RUN lines in here docs? Better defaults and/or an easier way to change the defaults would be good! The previous commenter is

So now you need to wrap all your RUN lines in here docs? Better defaults and/or an easier way to change the defaults would be good! The previous commenter is right -- it's all very well to say "just read all the docs" or "it's consistent with the way other tools work", but sometimes both the docs and the tools can be made less error-prone for users.