diff --git a/Dockerfile b/Dockerfile
index fc9b82f..0319ed6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,6 +10,8 @@ LABEL maintainer="Alexander Trost <galexrt@googlemail.com>"
 ARG ZULIP_GIT_URL=https://github.com/zulip/zulip.git
 ARG ZULIP_GIT_REF=master
 
+SHELL ["/bin/sh", "-xc"]
+
 # First, we setup working locales
 RUN echo 'APT::Install-Recommends 0;' >> /etc/apt/apt.conf.d/01norecommends && \
     echo 'APT::Install-Suggests 0;' >> /etc/apt/apt.conf.d/01norecommends && \
@@ -45,6 +47,8 @@ RUN /bin/bash -c "source /srv/zulip-py3-venv/bin/activate && ./tools/build-relea
 FROM ubuntu:xenial-20171114
 LABEL maintainer="Alexander Trost <galexrt@googlemail.com>"
 
+SHELL ["/bin/sh", "-xc"]
+
 ENV DATA_DIR="/data" \
     LANG="en_US.UTF-8" \
     LANGUAGE="en_US:en" \