anchor.diff:  FROM base/archlinux:2014.07.03
   
  +ENV LANG en_US.UTF-8
  +
  +# update sources and already installed packages
  +# (https://wiki.archlinux.org/index.php/pacman#Partial_upgrades_are_unsupported)
   RUN pacman -Syu --noconfirm
   
  -RUN pacman -S --noconfirm git
  -RUN pacman -S --noconfirm vim
  -RUN pacman -S --noconfirm tmux
  -RUN pacman -S --noconfirm base-devel curl man openssh sudo wget unzip
  +# build basics
  +RUN pacman -S --noconfirm base-devel curl man openssh sudo wget unzip yajl
   
  -RUN pacman -S --noconfirm bash-completion
  -RUN pacman -S --noconfirm ctags
  -RUN pacman -S --noconfirm docker
  -RUN pacman -S --noconfirm gtypist
  -RUN pacman -S --noconfirm parallel
  -
  +# yaourt
   WORKDIR /tmp
  -# yaourt
  -RUN pacman -S --noconfirm yajl
   RUN curl https://aur.archlinux.org/packages/pa/package-query/package-query.tar.gz | tar zx
   WORKDIR /tmp/package-query
   RUN makepkg --asroot --noconfirm -i
  
positive.code: RUN sudo pacman -S --noconfirm puppet
  RUN sudo gem install librarian-puppet --no-user-install
  ADD Puppetfile /tmp/Puppetfile
  RUN librarian-puppet install
  ADD manifests /tmp/manifests
  ADD files /tmp/files
  
negative.code: WORKDIR /tmp/yaourt
  RUN makepkg --asroot --noconfirm -i
  
  # development basics
  RUN pacman -S --noconfirm git vim tmux
  
  # my things
  RUN pacman -S --noconfirm bash-completion ctags docker gtypist parallel
  
  # 'dev' user
  RUN useradd --create-home dev
  ADD dev-sudoer /etc/sudoers.d/dev-sudoer
  ENV HOME /home/dev
  
  # workspace
  RUN mkdir /var/shared/
  RUN touch /var/shared/placeholder
  RUN chown -R dev:dev /var/shared
  VOLUME ['/var/shared']
  
  USER dev
  
  # ssh agent "forwarding"
  RUN mkdir /home/dev/.ssh
  RUN touch /home/dev/.ssh/known_hosts
  ENV SSH_AUTH_SOCK /home/dev/.ssh/ssh_auth_sock
  
  ADD tmux.conf /home/dev/.tmux.conf
  ADD gitignore /home/dev/.gitignore
  