Chapter 4 v4.18 - 4.3 Build Images with Advanced Containerfile Instructions - ARG instructions

[AlessandraS]

Hi, in this example when the following RUN command inside the Containerfile is executed

RUN curl "https://dl.example.io/${VERSION}/example-linux-amd64" \ -o ${BIN_DIR}/example

${VERSION} is valued to 1.16.8, but nowhere in the chapter is explained that if the ARG value is nil, then the ENV value is passed to ${VERSION}.

Am I right? Thanks