text: #!/bin/bash
  FN="cyp450cdf_2.18.0.tar.gz"
  URLS=(
    "https://bioconductor.org/packages/3.11/data/annotation/src/contrib/cyp450cdf_2.18.0.tar.gz"
    "https://bioarchive.galaxyproject.org/cyp450cdf_2.18.0.tar.gz"
    "https://depot.galaxyproject.org/software/bioconductor-cyp450cdf/bioconductor-cyp450cdf_2.18.0_src_all.tar.gz"
    "https://depot.galaxyproject.org/software/bioconductor-cyp450cdf/bioconductor-cyp450cdf_2.18.0_src_all.tar.gz"
  )
  MD5="7923c4d24b7b654d0f59d52ed2258eb9"
  
  # Use a staging area in the conda dir rather than temp dirs, both to avoid
  # permission issues as well as to have things downloaded in a predictable
  # manner.
  STAGING=$PREFIX/share/$PKG_NAME-$PKG_VERSION-$PKG_BUILDNUM
  mkdir -p $STAGING
  TARBALL=$STAGING/$FN
  
  SUCCESS=0
  for URL in ${URLS[@]}; do
    curl $URL > $TARBALL
    [[ $? == 0 ]] || continue
  
    # Platform-specific md5sum checks.
    if [[ $(uname -s) == "Linux" ]]; then
      if md5sum -c <<<"$MD5  $TARBALL"; then
        SUCCESS=1
        break
      fi
    else if [[ $(uname -s) == "Darwin" ]]; then
      if [[ $(md5 $TARBALL | cut -f4 -d " ") == "$MD5" ]]; then
        SUCCESS=1
        break
      fi
    fi
  fi
  done
  
  if [[ $SUCCESS != 1 ]]; then
    echo "ERROR: post-link.sh was unable to download any of the following URLs with the md5sum $MD5:"
    printf '%s\n' "${URLS[@]}"
    exit 1
  fi
  
  # Install and clean up
  R CMD INSTALL --library=$PREFIX/lib/R/library $TARBALL
  rm $TARBALL
  rmdir $STAGING
  