anchor.diff:     proto_1.0.0.tar.gz \
      reshape2_1.4.3.tar.gz \
      lazyeval_0.2.1.tar.gz \
  -   rlang_0.2.2.tar.gz \
      utf8_1.1.4.tar.gz \
      fansi_0.3.0.tar.gz \
      pillar_1.3.0.tar.gz \
  
positive.code: 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 \
  
negative.code:    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_1.0.2.tar.gz \
     https://archive.linux.duke.edu/cran/src/contrib/rlang_0.3.1.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/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_1.2.2.tar.gz \
  