message: Exit early on invalid arguments
  This will catch e.g. --destination=foo.example.com
diff: @@ -90,9 +90,7 @@ shw_err () {
  # Parse input arguments.
  while [[ $# -gt 0 ]] ; do
  - key="$1"
  -
  - case $key in
  + case $1 in
  -d|--destination)
  DESTINATION_CLUSTER="$2"
  shift # past argument
  @@ -112,6 +110,10 @@ while [[ $# -gt 0 ]] ; do
  DRY_RUN="TRUE"
  shift # past argument
  ;;
  + *)
  + echo "Invalid Argument: $1"
  + exit 3
  + ;;
  esac
  done
  