Passe Vairalbe em String Dockerfile
RUN ln -s /home/newuser/$sname /home/newuser/docker_entrypoint.sh
ENTRYPOINT ["/home/newuser/docker_entrypoint.sh"]
Jealous Jay
RUN ln -s /home/newuser/$sname /home/newuser/docker_entrypoint.sh
ENTRYPOINT ["/home/newuser/docker_entrypoint.sh"]