Docker file entry point command doesn’t allow me to enter interactive mode?

What I wish to do is: start docker interactive mode with /bin/bash, and automatically sources /etc/environment

I’ve this at the end of my Dockerfile:

RUN chmod o+x /etc/environment
ENTRYPOINT ["/bin/bash"]
CMD ["/bin/bash"]

I ran command:

sudo docker run -it myimage -c "/etc/environment"

It seems ok, but I don’t enter docker container. Seems ENTRYPOINT command will execute bash and quit?

Then I changed the entry point line to:

ENTRYPOINT ["/bin/bash", "-c", "source /etc/environment"]

And rebuilt the image.

 sudo docker run -it myimage

Again, seems to end after docker run at once. Doesn’t work either. How to fix it? Thanks a lot.

Source: StackOverflow