RUN curl -L "https://github.com/rust-lang/mdBook/releases/download/${MDBOOK_VERSION}/mdbook-${MDBOOK_VERSION}-x86_64-unknown-linux-gnu.tar.gz" | tar xvzf - mdbook \
RUN curl -L "https://github.com/rust-lang/mdBook/releases/download/${MDBOOK_VERSION}/mdbook-${MDBOOK_VERSION}-x86_64-unknown-linux-gnu.tar.gz" | tar xvzf - mdbook \