add upgrade cleanup functionality of dokuwiki (grep/find) and reorganise commands to save image space (18 MB, 10%)

Dockerfile

@@ -13,27 +13,28 @@ ENV DOKUWIKI_VERSION 2015-08-10a
 ENV DOKUWIKI_CSUM a4b8ae00ce94e42d4ef52dd8f4ad30fe
 
 ENV LAST_REFRESHED 6. September 2015
-# Update & install packages
-RUN apt-get update && apt-get -y upgrade
-RUN apt-get -y install wget \
-	lighttpd \
-	php5-cgi \
-	php5-gd
-
-# Download & deploy twiki
-RUN wget -O /dokuwiki.tgz \
-	"http://download.dokuwiki.org/src/dokuwiki/dokuwiki-$DOKUWIKI_VERSION.tgz"
-RUN if [ "$DOKUWIKI_CSUM" != "$(md5sum /dokuwiki.tgz | awk '{print($1)}')" ];\
-  then echo "Wrong md5sum of downloaded file!"; exit 1; fi;
-RUN tar -zxf dokuwiki.tgz
-RUN mv "/dokuwiki-$DOKUWIKI_VERSION" /dokuwiki
+
+# Update & install packages & cleanup afterwards
+RUN DEBIAN_FRONTEND=noninteractive \
+    apt-get update && \
+    apt-get -y upgrade && \
+    apt-get -y install wget lighttpd php5-cgi php5-gd && \
+    apt-get clean autoclean && \
+    apt-get autoremove && \
+    rm -rf /var/lib/{apt,dpkg,cache,log}
+
+# Download & check & deploy dokuwiki & cleanup
+RUN wget -q -O /dokuwiki.tgz "http://download.dokuwiki.org/src/dokuwiki/dokuwiki-$DOKUWIKI_VERSION.tgz" && \
+    if [ "$DOKUWIKI_CSUM" != "$(md5sum /dokuwiki.tgz | awk '{print($1)}')" ];then echo "Wrong md5sum of downloaded file!"; exit 1; fi && \
+    mkdir /dokuwiki && \
+    tar -zxf dokuwiki.tgz -C /dokuwiki --strip-components 1 && \
+    rm -rf dokuwiki.tgz && \
+    cd /dokuwiki && \
+    grep -Ev '^($|#)' data/deleted.files | xargs -n 1 rm -vrf
 
 # Set up ownership
 RUN chown -R www-data:www-data /dokuwiki
 
-# Cleanup
-RUN rm dokuwiki.tgz
-
 # Configure lighttpd
 ADD dokuwiki.conf /etc/lighttpd/conf-available/20-dokuwiki.conf
 RUN lighty-enable-mod dokuwiki fastcgi accesslog