anchor.diff:     formatR_1.4.tar.gz \
      highr_0.6.tar.gz \
      markdown_0.7.7.tar.gz \
  -   stringi_1.1.2.tar.gz \
  +   stringi_1.1.3.tar.gz \
      magrittr_1.5.tar.gz \
      stringr_1.2.0.tar.gz \
      knitr_1.15.1.tar.gz \
      yaml_2.1.14.tar.gz \
  -   Rcpp_0.12.9.tar.gz \
  +   Rcpp_0.12.19.tar.gz \
      htmltools_0.3.5.tar.gz \
      caTools_1.17.1.tar.gz \
      bitops_1.0-6.tar.gz \
  
positive.code:    http://archive.linux.duke.edu/cran/src/contrib/mime_0.5.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/httr_1.2.1.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/RCurl_1.95-4.8.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/Rcpp_0.12.9.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/BH_1.62.0-1.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/xml2_1.1.1.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/curl_2.3.tar.gz \
  
negative.code: RUN DEBIAN_FRONTEND=noninteractive wget \
     http://archive.linux.duke.edu/cran/src/contrib/knitr_1.15.1.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/yaml_2.1.14.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/Rcpp_0.12.19.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/htmltools_0.3.5.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/caTools_1.17.1.tar.gz \
     http://archive.linux.duke.edu/cran/src/contrib/bitops_1.0-6.tar.gz \
  