Updating PATH environment variable permanently in Docker container
If you want to include a /new/path in the Dockerfile, adding the line:
ENV PATH "$PATH:/new/path"
in Dockerfile should work.
1. The correct answer
The best voted answer suggests to add ENV PATH "$PATH:/new/path" to the Dockerfile, and this should indeed work.
2. So why doesn't it work for me?
As noted in some comments/answers, the solution 1. does not work for some people.
The reason is that the PATH can be overwritten by some script like .bashrc when running the docker container, giving thus the impression that the ENV PATH... did not work, but it theoretically did.
To solve the issue, you need to append to the .bashrc the correct PATH by adding the below command to your Dockerfile:
RUN echo "export PATH=/new/path:${PATH}" >> /root/.bashrc
Put in your Dockerfile a line ENV PATH xxx see an example in this Dockerfile https://gist.github.com/deepak/5933685