Docker: set ENV variable using RUN command?

Question

I am writing a Dockerfile to customize my customized WordPress environment. I start with ubuntu: the latter and would like to add some repositories dynamically by setting the ENV variable to the code name of the current version of Ubuntu. How can I do this, or is there a better way to achieve this?

Answer 1

Start your container as follows: docker run -e VAR=value -e ANOTHER_VAR=another_value .... VAR and ANOTHER_VAR will be available in the container environment.