anchor.diff:      https://archive.linux.duke.edu/cran/src/contrib/microbenchmark_1.4-4.tar.gz \
       https://archive.linux.duke.edu/cran/src/contrib/modelr_0.1.2.tar.gz \
       https://archive.linux.duke.edu/cran/src/contrib/clipr_0.4.1.tar.gz \
  -    https://archive.linux.duke.edu/cran/src/contrib/ps_1.1.0.tar.gz \
       https://archive.linux.duke.edu/cran/src/contrib/globals_0.12.2.tar.gz \
       https://archive.linux.duke.edu/cran/src/contrib/listenv_0.7.0.tar.gz \
       https://archive.linux.duke.edu/cran/src/contrib/iterators_1.0.10.tar.gz \
  
positive.code:    downloader_0.4.tar.gz
  
  RUN rm \
     callr_3.2.0.tar.gz \
     processx_3.3.0.tar.gz \
     cli_1.1.0.tar.gz \
     pkgbuild_1.0.2.tar.gz \
  
negative.code:    bitops_1.0-6.tar.gz \
     RCurl_1.95-4.12.tar.gz \
     plyr_1.8.4.tar.gz \
     httr_1.4.0.tar.gz \
     rstudioapi_0.10.tar.gz \
     sys_3.1.tar.gz \
  