anchor.diff:  # tools
   RUN apt-get install -y dnsutils bash-completion xsltproc \
       build-essential fakeroot tmux duplicity lftp htop apt-file \
  -    parallel nano strace ltrace flex jq ack-grep gdb valgrind locate tree time
  +    parallel nano strace ltrace flex jq ack-grep gdb valgrind locate tree time \
  +    zip
   
   # Version control
   RUN apt-get install -y git-all tig subversion subversion-tools cvs \
  
positive.code:     mkdir -p /data/db && \
      sudo chown ubuntu:ubuntu /data/db && \
      echo "Configure apache2" && \
      sudo sed -i 's/Listen 80\b/Listen 8080/' /etc/apache2/ports.conf && \
      ln -s /etc/apache2/sites-available/001-cloud9.conf /etc/apache2/sites-enabled && \
      chmod 644 /etc/apache2/sites-available/001-cloud9.conf && \
  
negative.code: 
  # all changes go down here:
  # RUN ...
  
  # setup the system
  RUN echo -n "" > /etc/motd && \
  