anchor.diff:  RUN DEBIAN_FRONTEND=noninteractive wget \
      https://archive.linux.duke.edu/cran/src/contrib/lubridate_1.7.4.tar.gz \
      https://archive.linux.duke.edu/cran/src/contrib/lazyeval_0.2.1.tar.gz \
  -   https://archive.linux.duke.edu/cran/src/contrib/rlang_0.2.2.tar.gz \
      https://archive.linux.duke.edu/cran/src/contrib/utf8_1.1.4.tar.gz \
      https://archive.linux.duke.edu/cran/src/contrib/fansi_0.3.0.tar.gz \
      https://archive.linux.duke.edu/cran/src/contrib/pillar_1.3.0.tar.gz \
  
positive.code:    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 \
     askpass_1.1.tar.gz \
     openssl_1.2.2.tar.gz \
  
negative.code:    askpass_1.1.tar.gz \
     openssl_1.2.2.tar.gz \
     httr_1.4.0.tar.gz \
     git2r_0.25.2.tar.gz \
     devtools_2.0.1.tar.gz \
     brew_1.0-6.tar.gz \
  