anchor.diff:  ENV PETPVC_GIT https://github.com/UCL/PETPVC.git
   ENV CAMINO_GIT git://git.code.sf.net/p/camino/code
   ENV ANTS_GIT https://github.com/stnava/ANTs.git
  -
  +ENV PYENV_NAME pytre
   
   # Install.
   RUN \
  
positive.code: RUN \
      pip instal virtualenvwrapper && \
      source /usr/local/bin/virtualenvwrapper.sh && \
      mkvirtualenv -p /usr/bin/python3 pytre && \
      pip install -r root/pypes_requirements.txt
  
  ENV WORKON_HOME $HOME/pyenvs
  
negative.code:     echo "VIRTUALENVWRAPPER_PYTHON=`which python3`" >> $BASHRC && \
      echo "source /usr/local/bin/virtualenvwrapper.sh" >> $BASHRC && \
      echo "export WORKON_HOME=$HOME/pyenvs" >> $BASHRC && \
      echo "workon $PYENV_NAME" >> $BASHRC
  
  #-------------------------------------------------------------------------------
  # source .bashrc
  