#!/bin/bash

readonly program="$(basename "${0}")"

function usage {
  echo "
    List pkg receipt IDs for the 10 most recently installed packages. Package IDs attributed to Apple are excluded from the output.

    Usage:
      ${program} [options]

    Options:
      -h, --help   Show this message.
  " | sed -E 's/ {4}//'
}

if [[ "${1}" =~ ^(-h|--help)$ ]]; then
  usage
  exit 0
fi

/bin/ls -t /var/db/receipts | \
  /usr/bin/grep '\.plist$' | \
  /usr/bin/grep --invert-match '^com\.apple\.' | \
  /usr/bin/sed 's/\.plist$//' | \
  /usr/bin/head -10