How to use sudo inside a docker container?

Question

Normally, docker containers are run using the user root. I\'d like to use a different user, which is no problem using docker\'s USER directive. But this use

Answer 1

This may not work for all images, but some images contain a root user already, such as in the jupyterhub/singleuser image. With that image it's simply:

USER root
RUN sudo apt-get update