#!/bin/sh
usage() {
  echo "Usage:

  $(basename "$0") [-h] <volume> -- generate /etc/fstab entry to prevent automount on macOS

  where:
    -h      print this help
    volume  the volume that should not be automounted
"
}

error() {
  usage
  echo "$(tput setaf 1)ERROR: $1$(tput sgr0)"
  exit 1
}>&2

gen_fstab_entry() {
  volume="$1"
  info="$(diskutil info "$volume")"
  uuid=$(echo "$info" | grep 'Volume UUID' | sed -e 's/^ *Volume UUID: *//')
  fs=$(echo "$info" | grep 'Type (Bundle)' | sed -e 's/^ *Type (Bundle): *//')
  echo "# $volume"
  echo "UUID=$uuid none $fs rw,noauto"
  echo
}

case "$1" in
  -h|--help)  usage ;;
  -*)         error "invalid option: $1" ;;
  "")         error "volume required" ;;
  *)          gen_fstab_entry "$1";;
esac