'set -o nounset' is a must have. I Just suffered this script from Samsung Printer setting Utility. sudo ./uninstall wiped the /opt

  DEST_PATH=/opt/$VENDOR/$DEST_DIRNAME
  #remove destination
  VERSION=`cat "$DEST_PATH/bin/.version"`
  if rm -fr "$DEST_PATH"; then
  	echo "INFO: $APP_NAME (ver.$VERSION) has been uninstalled successfully."
  ...