anchor.diff:     RCurl_1.95-4.12.tar.gz \
      plyr_1.8.4.tar.gz \
      httr_1.4.0.tar.gz \
  -   sys_3.1.tar.gz \
  +   sys_3.2.tar.gz \
      askpass_1.1.tar.gz \
  -   openssl_1.3.tar.gz \
  +   openssl_1.4.tar.gz \
      brew_1.0-6.tar.gz \
      roxygen2_5.0.1.tar.gz \
      BH_1.69.0-1.tar.gz \
  -   XML_3.98-1.19.tar.gz \
  +   XML_3.98-1.20.tar.gz \
      xml2_1.2.0.tar.gz \
      curl_3.3.tar.gz \
  -   rversions_1.0.3.tar.gz \
  +   rversions_2.0.0.tar.gz \
      git2r_0.25.2.tar.gz \
  -   devtools_2.0.1.tar.gz \
  +   devtools_2.0.2.tar.gz \
      downloader_0.4.tar.gz
   
   # the CRAN install from source fails because a server at MIT will not respond
  
positive.code:    https://archive.linux.duke.edu/cran/src/contrib/cli_1.1.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/desc_1.2.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/prettyunits_1.0.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/backports_1.1.3.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/rprojroot_1.3-2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/withr_2.1.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/pkgbuild_1.0.3.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/rlang_0.3.3.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/rstudioapi_0.10.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/pkgload_1.0.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/rcmdcheck_1.3.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/remotes_2.0.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/xopen_1.0.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/clipr_0.5.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/clisymbols_1.2.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/sessioninfo_1.1.1.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/usethis_1.4.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/sys_3.1.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/askpass_1.1.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/openssl_1.3.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/brew_1.0-6.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/Archive/roxygen2/roxygen2_5.0.1.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/fs_1.2.7.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/gh_1.0.1.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/rversions_1.0.3.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/git2r_0.25.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/devtools_2.0.1.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/R6_2.4.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/httr_1.4.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/RCurl_1.95-4.12.tar.gz \
  
negative.code:    https://archive.linux.duke.edu/cran/src/contrib/downloader_0.4.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/memoise_1.1.0.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/plyr_1.8.4.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/XML_3.98-1.20.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/whisker_0.3-2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/bitops_1.0-6.tar.gz
  
  RUN DEBIAN_FRONTEND=noninteractive R CMD INSTALL \
     ps_1.3.0.tar.gz \
     R6_2.4.0.tar.gz \
     processx_3.3.1.tar.gz \
     callr_3.2.0.tar.gz \
     crayon_1.3.4.tar.gz \
     assertthat_0.2.1.tar.gz \
     cli_1.1.0.tar.gz \
     backports_1.1.4.tar.gz \
     rprojroot_1.3-2.tar.gz \
     desc_1.2.0.tar.gz \
     prettyunits_1.0.2.tar.gz \
     withr_2.1.2.tar.gz \
     pkgbuild_1.0.3.tar.gz \
     rlang_0.3.4.tar.gz \
     rstudioapi_0.10.tar.gz \
     pkgload_1.0.2.tar.gz \
     xopen_1.0.0.tar.gz \
     sessioninfo_1.1.1.tar.gz \
     rcmdcheck_1.3.3.tar.gz \
     remotes_2.0.4.tar.gz \   
     whisker_0.3-2.tar.gz \
     git2r_0.25.2.tar.gz \
     fs_1.3.1.tar.gz \
     ini_0.3.1.tar.gz \
     jsonlite_1.6.tar.gz \
     sys_3.2.tar.gz \
     askpass_1.1.tar.gz \
     openssl_1.4.tar.gz \
     curl_3.3.tar.gz \
     httr_1.4.0.tar.gz \
     gh_1.0.1.tar.gz \
     clipr_0.6.0.tar.gz \
     clisymbols_1.2.0.tar.gz \   
     usethis_1.5.0.tar.gz \
     memoise_1.1.0.tar.gz \
     bitops_1.0-6.tar.gz \
     RCurl_1.95-4.12.tar.gz \
     plyr_1.8.4.tar.gz \
     devtools_2.0.2.tar.gz \
     brew_1.0-6.tar.gz \
     roxygen2_5.0.1.tar.gz \
     XML_3.98-1.20.tar.gz \
     BH_1.69.0-1.tar.gz \
     xml2_1.2.0.tar.gz \
     rversions_2.0.0.tar.gz \
     downloader_0.4.tar.gz
  
  RUN rm \
     ps_1.3.0.tar.gz \
     callr_3.2.0.tar.gz \
     R6_2.4.0.tar.gz \
     processx_3.3.1.tar.gz \
     crayon_1.3.4.tar.gz \
     assertthat_0.2.1.tar.gz \
     cli_1.1.0.tar.gz \
     desc_1.2.0.tar.gz \
     prettyunits_1.0.2.tar.gz \
     backports_1.1.4.tar.gz \
     rprojroot_1.3-2.tar.gz \
     withr_2.1.2.tar.gz \
     pkgbuild_1.0.3.tar.gz \
     rlang_0.3.4.tar.gz \
     rstudioapi_0.10.tar.gz \
     clipr_0.6.0.tar.gz \
     clisymbols_1.2.0.tar.gz \
     pkgload_1.0.2.tar.gz \
     sessioninfo_1.1.1.tar.gz \
     xopen_1.0.0.tar.gz \
     rcmdcheck_1.3.3.tar.gz \
     remotes_2.0.4.tar.gz \
     usethis_1.5.0.tar.gz \
     ini_0.3.1.tar.gz \
     jsonlite_1.6.tar.gz \
     memoise_1.1.0.tar.gz \
  