anchor.diff:  FROM ubuntu:18.04 AS base
   MAINTAINER vgteam
   
  +RUN echo base > /stage.txt
  +
   WORKDIR /vg
  +
  +RUN ls -lah /vg || echo "No vg directory exists yet"
   
   FROM base AS build
   
  +RUN echo build > /stage.txt
  +
  +RUN ls -lah /vg || echo "No vg directory exists yet"
  +
   # Copy vg build tree into place
   COPY . /vg
  +
  +RUN ls -lah /vg || echo "No vg directory exists yet"
   
   # Install the base packages needed to let vg install packages.
   # Make sure this runs after vg sources are imported so vg will always have an
  
positive.code: ############################################################################################
  FROM base AS run
  
  COPY --from=build /vg/bin/vg /vg/bin/
  
  COPY --from=build /vg/scripts/* /vg/scripts/
  
  # Install packages which toil-vg needs to be available inside the image, for pipes
  # TODO: which of these can be removed?
  
negative.code: 
  ############################################################################################
  FROM build AS test
  
  RUN echo test > /stage.txt
  
  # The test need BWA
  COPY --from=quay.io/ucsc_cgl/bwa:0.7.15--a17c6544342330f6ea7a23a37d23273ab1c52d21 /usr/local/bin/bwa /usr/local/bin/bwa
  