Yes, it was right, but nowadays Dockerfiles are not specific to Docker. Dockerfiles also work with Buildah & Podman (and there might be other ones in the future) and they have generalized the naming: “Containerfile.”

For path names with newlines it is better to quote each pathname.

The non-determinism is why cache invalidation — and that other hard problem, naming things — are uniquely and intractably hard problems in computer science. Computers can perfectly solve deterministic problems. But they can’t predict when to invalidate a cache because, ultimately, we, the humans who design and build computational processes, can’t agree on when a cache needs to be invalidated.

Unfortunately, many third party libraries, even though they are written in ESM, are published to npm as CJS modules, so we still need to concatenate them.