anchor.diff:  ENV PROTOTOOL_VERSION=7df3b957ffe3d09dc57fe4e1eb96694614db8c7a
   ENV SHELLCHECK_VERSION=v0.7.0
   ENV UPX_VERSION=3.95
  -ENV DOCKER_VERSION=18.06.1~ce~3-0
   ENV KIND_VERSION=v0.5.1
   
   WORKDIR /tmp
  
positive.code: 
  FROM ubuntu:xenial as base_os_context
  
  # required for binary tools: ca-certificates, gcc, libc-dev, git, iptables, libltdl7
  # required for general build: make, wget, curl
  # required for ruby: libcurl4-openssl-dev
  # required for python: python3, pkg-config
  # hadolint ignore=DL3008
  RUN apt-get update && apt-get install -y --no-install-recommends \
      ca-certificates \
      curl \
      gcc \
      git \
      iptables \
  
negative.code:     pkg-config \
      python3 \
      wget
  
  # Docker including docker-ce, docker-ce-cli, and containerd.io
  ADD https://download.docker.com/linux/ubuntu/gpg /tmp/docker-key
  RUN apt-key add /tmp/docker-key
  RUN add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu xenial stable"
  RUN apt-get update
  RUN apt-get -y install --no-install-recommends docker-ce="${DOCKER_VERSION}" docker-ce-cli="${DOCKER_VERSION}" containerd.io="${CONTAINERD_VERSION}"
  
  # Clean up stuff we don't need in the final image
  RUN rm -rf /var/lib/apt/lists/*
  