valoarea implicită a variabilelor de mediu dockerfile
ARG DB_HOST=default-value
ENV DB_HOST=$DB_HOST
docker ARG
$ docker build --build-arg some_variable_name=a_value
dockerfile VAR
ENV abc=hello
ENV abc=bye def=$abc
ENV ghi=$abc
dockerfile env variabes
FROM busybox
ENV foo /bar
WORKDIR ${foo} # WORKDIR /bar
ADD . $foo # ADD . /bar
COPY \$foo /quux # COPY $foo /quux