anchor.diff:  ARG INSTALL_GNU_PARALLEL=false
   
   RUN if [ ${INSTALL_GNU_PARALLEL} = true ]; then \
  -  apt-get -y install parallel \
  +  apt-get -yqq install parallel \
   ;fi
   
   ###########################################################################
  
positive.code: ARG INSTALL_LNAV=false
  
  RUN if [ ${INSTALL_LNAV} = true ]; then \
      apt-get install -y lnav \
  ;fi
  
  ###########################################################################
  
negative.code: 
  RUN if [ ${INSTALL_PG_CLIENT} = true ]; then \
      # Install the pgsql client
      apt-get -yqq install wget \
      && wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add - \
      && echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" | tee /etc/apt/sources.list.d/pgdg.list \
      && apt-get update \
  