Docker stopsignal debugging

Dockerfile

FROM ubuntu:latest

COPY signals.sh signals.sh

ENV        STOPSIGNAL=SIGTERM
STOPSIGNAL ${STOPSIGNAL}

ENTRYPOINT ["/bin/bash"]
CMD ["./signals.sh"]

signals.sh

trap "echo sigterm; exit 0" TERM
trap "echo sigquit; exit 0" QUIT

echo stopsignal is \"$STOPSIGNAL\"

echo waiting
while true; do sleep 1; done