chore(Dockerfile): cleanup after installation a bit more than before and keep copyright / license files (#434)

Author: helgi

rootfs/Dockerfile

@@ -7,23 +7,40 @@ RUN adduser --system \
 	--group \
 	git
 
-RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E1DF1F24 \
-	&& echo "deb http://ppa.launchpad.net/git-core/ppa/ubuntu xenial main" >> /etc/apt/sources.list \
-	&& apt-get update \
-	&& apt-get install -y \
+RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E1DF1F24 && \
+	echo "deb http://ppa.launchpad.net/git-core/ppa/ubuntu xenial main" >> /etc/apt/sources.list && \
+	apt-get update && \
+	apt-get install -y --no-install-recommends \
 		git \
 		sudo \
 		openssh-server \
 		coreutils \
 		tar \
-		xz-utils \
-		--no-install-recommends \
-	&& mkdir -p /var/run/sshd \
-	&& rm -rf /etc/ssh/ssh_host* \
-	&& mkdir /apps \
-	&& apt-get clean \
-	&& rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* /usr/share/man /usr/share/doc \
-	&& passwd -u git
+		xz-utils && \
+	mkdir -p /var/run/sshd && \
+	rm -rf /etc/ssh/ssh_host* && \
+	mkdir /apps && \
+	passwd -u git && \
+    # cleanup
+    apt-get autoremove -y && \
+    apt-get clean -y && \
+    # package up license files if any by appending to existing tar
+    COPYRIGHT_TAR='/usr/share/copyrights.tar'; \
+    gunzip $COPYRIGHT_TAR.gz; tar -rf $COPYRIGHT_TAR /usr/share/doc/*/copyright; gzip $COPYRIGHT_TAR && \
+    rm -rf \
+        /usr/share/doc \
+        /usr/share/man \
+        /usr/share/info \
+        /usr/share/locale \
+        /var/lib/apt/lists/* \
+        /var/log/* \
+        /var/cache/debconf/* \
+        /etc/systemd \
+        /lib/lsb \
+        /lib/udev \
+        /usr/lib/x86_64-linux-gnu/gconv/IBM* \
+        /usr/lib/x86_64-linux-gnu/gconv/EBC* && \
+    bash -c "mkdir -p /usr/share/man/man{1..8}"
 
 COPY . /