anchor.diff:  RUN DEBIAN_FRONTEND=noninteractive R CMD INSTALL \
      bitops_1.0-6.tar.gz \
      caTools_1.17.1.tar.gz \
  -   digest_0.6.8.tar.gz \
  -   htmltools_0.2.6.tar.gz \
  +   digest_0.6.9.tar.gz \
  +   htmltools_0.3.tar.gz \
      yaml_2.1.13.tar.gz \
      stringi_1.0-1.tar.gz \
      magrittr_1.5.tar.gz \
  
positive.code:    http://mirrors.nics.utk.edu/cran/src/contrib/magrittr_1.5.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/lazyeval_0.1.10.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/DBI_0.3.1.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/BH_1.58.0-1.tar.gz 
  
  
  RUN DEBIAN_FRONTEND=noninteractive R CMD INSTALL \
  
negative.code: 
  # update the R packages we will need for knitr
  RUN DEBIAN_FRONTEND=noninteractive wget \
     http://mirrors.nics.utk.edu/cran/src/contrib/knitr_1.12.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/yaml_2.1.13.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/htmltools_0.3.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/caTools_1.17.1.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/bitops_1.0-6.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/digest_0.6.9.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/stringr_1.0.0.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/markdown_0.7.7.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/highr_0.5.1.tar.gz \
  