# Parse command line options
# =========================================================================== #
# This is an example script for using both long and short flags without using getopt (which is nonstandard)
# Copy paste from 
#   https://stackoverflow.com/questions/402377/using-getopts-to-process-long-and-short-command-line-options

die() { echo "$*" >&2; exit 2; }  # complain to STDERR and exit with error
needs_arg() { if [ -z "$OPTARG" ]; then die "No arg for --$OPT option"; fi; }

while getopts ab:c-: OPT; do
  if [ "$OPT" = "-" ]; then   # long option: reformulate OPT and OPTARG
    OPT="${OPTARG%%=*}"       # extract long option name
    OPTARG="${OPTARG#$OPT}"   # extract long option argument (may be empty)
    OPTARG="${OPTARG#=}"      # if long option argument, remove assigning `=`
  fi
  case "$OPT" in
    a | alpha )    ALPHA=true ;;
    b | bravo )    needs_arg; BRAVO="$OPTARG" ;;
    c | charlie )  CHARLIE=true ;;
    ??* )          die "Illegal option --$OPT" ;;  # bad long option
    \? )           exit 2 ;;  # bad short option (error reported via getopts)
  esac
done
shift $((OPTIND-1)) # remove parsed options and args from $@ list