[Shell] Download Python and R packages

download_pkg.sh

#!/usr/bin/env bash
#
# Usage:
#   ./download_pkg.sh \
#     --py-pkg ./py_requirements.txt \
#     --r-pkg ./r_requirements.txt \
#     --py-dir ./src/py \
#     --r-dir ./src/r
#
# Options:
#   -h, --help    Print usage
#   --py-pkg      Read a text file and download listed Python packages in that
#   --r-pkg       Read a text file and download listed R packages in that
#   --py-dir      Set a destination directory for Python packages [default: ./py]
#   --r-dir       Set a destination directory for R packages [default: ./r]
#
# Description:
#   A script to download sources of Python and R packages

set -e

# Set default values
SCRIPT_PATH="${0}"
PY_DIR='./py'
R_DIR='./r'
PY_TXT=false
R_TXT=false

function print_usage {
  sed -ne '1,2d; /^#/!q; s/^#$/# /; s/^# //p;' ${SCRIPT_PATH}
}

# Parse options
while [[ -n "${1}" ]]; do
  case "${1}" in
    '-h' | '--help' )
      print_usage && exit 0
      ;;
    '--debug' )
      set -x && shift 1
      ;;
    '--py-pkg' )
      PY_TXT="${2}" && shift 2
      ;;
    '--py-dir' )
      PY_DIR="${2}" && shift 2
      ;;
    '--r-pkg' )
      R_TXT="${2}" && shift 2
      ;;
    '--r-dir' )
      R_DIR="${2}" && shift 2
      ;;
    * )
      print_usage && exit 1
      ;;
  esac
done

set -u

# Check requirements
pip --version
R --version

# Download Python packages
if [[ -f "${PY_TXT}" ]]; then
  [[ -d "${PY_DIR}" ]] || mkdir -p ${PY_DIR}
  pip download --dest ${PY_DIR} --requirement ${PY_TXT}
  echo '
  Install Python packages:
    $ pip install /path/to/py-dir/*'
fi

# Download R packages
if [[ -f "${R_TXT}" ]]; then
  [[ -d "${R_DIR}" ]] || mkdir -p ${R_DIR}
  R -q -e "download.packages(read.table('${R_TXT}')[, 1], destdir = '${R_DIR}', type = 'source', repos = 'https://cran.rstudio.com/');"
  echo '
  Install R packages:
    $ R CMD INSTALL /path/to/r-dir/*'
fi