anchor.diff:  
   # Ruby
   RUN git clone git://github.com/rbenv/rbenv.git /usr/local/rbenv \
  -&&  git clone git://github.com/rbenv/ruby-build.git /usr/local/rbenv/plugins/ruby-build \
  -&&  git clone git://github.com/jf/rbenv-gemset.git /usr/local/rbenv/plugins/rbenv-gemset \
  -&&  /usr/local/rbenv/plugins/ruby-build/install.sh
  +	&&  git clone git://github.com/rbenv/ruby-build.git /usr/local/rbenv/plugins/ruby-build \
  +	&&  git clone git://github.com/jf/rbenv-gemset.git /usr/local/rbenv/plugins/rbenv-gemset \
  +	&&  /usr/local/rbenv/plugins/ruby-build/install.sh
   ENV PATH /usr/local/rbenv/bin:$PATH
   ENV RBENV_ROOT /usr/local/rbenv
   
   RUN echo 'export RBENV_ROOT=/usr/local/rbenv' >> /etc/profile.d/rbenv.sh \
  -&&  echo 'export PATH=/usr/local/rbenv/bin:$PATH' >> /etc/profile.d/rbenv.sh \
  -&&  echo 'eval "$(rbenv init -)"' >> /etc/profile.d/rbenv.sh
  +	&&  echo 'export PATH=/usr/local/rbenv/bin:$PATH' >> /etc/profile.d/rbenv.sh \
  +	&&  echo 'eval "$(rbenv init -)"' >> /etc/profile.d/rbenv.sh
   
   RUN echo 'export RBENV_ROOT=/usr/local/rbenv' >> /root/.bashrc \
  -&&  echo 'export PATH=/usr/local/rbenv/bin:$PATH' >> /root/.bashrc \
  -&&  echo 'eval "$(rbenv init -)"' >> /root/.bashrc
  +	&&  echo 'export PATH=/usr/local/rbenv/bin:$PATH' >> /root/.bashrc \
  +	&&  echo 'eval "$(rbenv init -)"' >> /root/.bashrc
   
   ENV CONFIGURE_OPTS --disable-install-doc
   ENV PATH /usr/local/rbenv/bin:/usr/local/rbenv/shims:$PATH
   
   RUN eval "$(rbenv init -)"; rbenv install 2.5.3 \
  -&&  eval "$(rbenv init -)"; rbenv global 2.5.3 \
  -&&  eval "$(rbenv init -)"; gem update --system \
  -&& eval "$(rbenv init -)"; gem install bundler --force
  +	&&  eval "$(rbenv init -)"; rbenv global 2.5.3 \
  +	&&  eval "$(rbenv init -)"; gem update --system \
  +	&& eval "$(rbenv init -)"; gem install bundler --force
   
   # Python
   ENV LANG=C.UTF-8 LC_ALL=C.UTF-8
   ENV PATH /opt/conda/bin:$PATH
   
   RUN apt-get update --fix-missing && \
  -    apt-get install -y wget bzip2 ca-certificates curl git && \
  -    apt-get clean && \
  -    rm -rf /var/lib/apt/lists/*
  +	apt-get install -y wget bzip2 ca-certificates curl git && \
  +	apt-get clean && \
  +	rm -rf /var/lib/apt/lists/*
   
   RUN wget --quiet https://repo.anaconda.com/miniconda/Miniconda3-4.5.12-Linux-x86_64.sh -O ~/miniconda.sh && \
  -    /bin/bash ~/miniconda.sh -b -p /opt/conda && \
  -    rm ~/miniconda.sh && \
  -    /opt/conda/bin/conda clean -tipsy && \
  -    ln -s /opt/conda/etc/profile.d/conda.sh /etc/profile.d/conda.sh && \
  -    echo ". /opt/conda/etc/profile.d/conda.sh" >> ~/.bashrc && \
  -    echo "conda activate base" >> ~/.bashrc
  +	/bin/bash ~/miniconda.sh -b -p /opt/conda && \
  +	rm ~/miniconda.sh && \
  +	/opt/conda/bin/conda clean -tipsy && \
  +	ln -s /opt/conda/etc/profile.d/conda.sh /etc/profile.d/conda.sh && \
  +	echo ". /opt/conda/etc/profile.d/conda.sh" >> ~/.bashrc && \
  +	echo "conda activate base" >> ~/.bashrc
   
   RUN conda update conda
   RUN conda install --yes numpy scipy cython 
  
positive.code: 
  # adapted from drecom/ubuntu-base drecom/ubuntu-ruby
  RUN apt-get update \
  &&  apt-get upgrade -y --force-yes \
  &&  apt-get install -y --force-yes \
      libssl-dev \
      libreadline-dev \
      zlib1g-dev \
      wget \
      curl \
      git \
      build-essential \
      vim \
      dtach \
      imagemagick \
      libmagick++-dev \
      libqtwebkit-dev \
      libffi-dev \
      mysql-client \
      libmysqlclient-dev \
      libxslt1-dev \
      redis-tools \
      xvfb \
      tzdata \
  	  libyaml-dev \
  	  libsqlite3-dev \
  	  sqlite3 \
  	  libxml2-dev \
  	  libcurl4-openssl-dev \
  &&  apt-get clean \
  &&  rm -rf /var/cache/apt/archives/* /var/lib/apt/lists/*
  
  # node.js LTS install
  RUN curl --silent --location https://deb.nodesource.com/setup_10.x | bash - \
      && apt-get install -y nodejs \
      && npm -g up
  
  # yarn install
  RUN curl -o- -L https://yarnpkg.com/install.sh | bash
  
negative.code: ENV THRIFT_VERSION 0.11.0
  
  RUN buildDeps=" \
  	automake \
  	bison \
  	curl \
  	flex \
  	g++ \
  	libboost-dev \
  	libboost-filesystem-dev \
  	libboost-program-options-dev \
  	libboost-system-dev \
  	libboost-test-dev \
  	libevent-dev \
  	libssl-dev \
  	libtool \
  	make \
  	pkg-config \
  	"; \
  	apt-get update && apt-get install -y --no-install-recommends $buildDeps && rm -rf /var/lib/apt/lists/* \
  	&& curl -sSL "http://apache.mirrors.spacedump.net/thrift/$THRIFT_VERSION/thrift-$THRIFT_VERSION.tar.gz" -o thrift.tar.gz \
  