Docker from Dockerfile with "nc" does not show anything - docker

Question

I am running the following Docker container from these Dockerfiles:
FROM debian:wheezy
MAINTAINER authors "authors#gm.com"
RUN groupadd -r -g 2200 example && \
useradd -rM -g example -u 2200 example
ENV APPROOT="/app" \
APP="mailer.sh" \
VERSION="0.6"
LABEL base.name="Mailer Archetype" \
base.version="${VERSION}"
WORKDIR $APPROOT
ADD . $APPROOT
ENTRYPOINT ["/app/mailer.sh"]
EXPOSE 33333
and
FROM dockerinaction/mailer-base:0.6
COPY ["./log-impl", "${APPROOT}"]
RUN chmod a+x ${APPROOT}/${APP} && \
chown example:example /var/log
USER example:example
VOLUME ["/var/log"]
CMD ["/var/log/mailer.log"]
where the mailer.sh is:
#!/bin/sh
printf "Logging Mailer has started.\n"
while true
do
MESSAGE=$(nc -l -p 33333)
printf "[Message]: %s\n" "$MESSAGE" > $1
sleep 1
done
All starts. But I want to test it. So i tried:
from the host to run "nc 33333" -> nothing happens!
to attach to the container: "docker exec -it /bin/bash" but then it does not recognize basic commands like "ps", "vi", "nc"...
So I am afraid my script is just not running.
Why is that?
thanks