anchor.diff:  # install commands
   # airstack core utilities
   ADD core /package/airstack/core
  -RUN set -e; mkdir -v /command; ln -sv /package/airstack/core/command/* /command/
  +RUN mkdir -v /command; ln -sv /package/airstack/core/command/* /command/
   
   # To minimize rebuilds, binaries that are modified less often should be in earlier RUN commands.
   
  
positive.code: RUN /command/core-package-install haproxy
  
  # Packages::serf
  RUN \
    set -e; \
    VER="0.6.3"; PKG_NAME="serf" PKG_DIR="/package/$PKG_NAME"; mkdir -vp "$PKG_DIR-$VER"/command; \
    cd $PKG_DIR-$VER; \
    wget -v -O "$PKG_NAME-$VER".zip https://dl.bintray.com/mitchellh/serf/"$VER"_linux_amd64.zip; \
  
negative.code:   mv -f /usr/local/bin/$i'{new}' /usr/local/bin/$i
  
  # Packages::Lua
  RUN set -e; \
    /command/core-package-install libssl-dev luajit luarocks; \
    luarocks install --server=http://rocks.moonscript.org luasec OPENSSL_LIBDIR=/usr/lib/x86_64-linux-gnu/; \
    luarocks install --server=https://rocks.moonscript.org moonrocks
  
  