anchor.diff:  
   RUN rm \
       pryr_0.1.4.tar.gz \
  +    htmlwidgets_1.2.tar.gz \
       profvis_0.3.5.tar.gz \
       RcppArmadillo_0.9.100.5.0.tar.gz \
       xaringan_0.7.tar.gz \
  
positive.code: 
  RUN DEBIAN_FRONTEND=noninteractive wget \
      https://mirrors.nics.utk.edu/cran/src/contrib/pryr_0.1.4.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/profvis_0.3.5.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/RcppArmadillo_0.9.100.5.0.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/xaringan_0.7.tar.gz \
  
negative.code:     miniUI_0.1.1.1.tar.gz 
  
  RUN DEBIAN_FRONTEND=noninteractive wget \
      https://mirrors.nics.utk.edu/cran/src/contrib/nycflights13_1.0.0.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/abynames_0.3.0.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/janeaustenr_0.1.5.tar.gz \
  