anchor.diff:  
   RUN rm \
      jsonlite_1.5.tar.gz \
  -   digest_0.6.15.tar.gz \
  +   digest_0.6.16.tar.gz \
      memoise_1.1.0.tar.gz \
      whisker_0.3-2.tar.gz \
      bitops_1.0-6.tar.gz \
      RCurl_1.95-4.10.tar.gz \
  -   Rcpp_0.12.16.tar.gz \
      plyr_1.8.4.tar.gz \
      R6_2.2.2.tar.gz \
      mime_0.5.tar.gz \
  
positive.code:    tibble_1.4.2.tar.gz \
     bindr_0.1.1.tar.gz \
     bindrcpp_0.2.2.tar.gz \
     glue_1.2.0.tar.gz \
     pkgconfig_2.0.1.tar.gz \
     plogr_0.2.0.tar.gz \
     dplyr_0.7.4.tar.gz 
  
negative.code:    https://mirrors.nics.utk.edu/cran/src/contrib/mime_0.5.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/httr_1.3.1.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/RCurl_1.95-4.10.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/BH_1.66.0-1.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/xml2_1.2.0.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/curl_3.2.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/jsonlite_1.5.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/digest_0.6.16.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/downloader_0.4.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/memoise_1.1.0.tar.gz \
     https://mirrors.nics.utk.edu/cran/src/contrib/plyr_1.8.4.tar.gz \
  