Example of parsing sub commands in a function with getopts

example_get_opts.sh

function get_help() {
  cat <<help_message

--- script subcommand -------------------------------------------------------------

Commands related to this script

USAGE:
  script command shell [FLAGS] [SUBCOMMAND]

FLAGS:
  -H  Prints help information

SUBCOMMANDS:
  all                  Do everything (blah, blah2) [default]

help_message

  return 1
}

function get_opts() {
  #  Parse options to the main command.
  while getopts ":H" opt; do
    case "${opt}" in
      H)
        #  Display help.
        get_help
        ;;
      \?)
        #  Unrecognized option, get help.
        libs_log::error "Invalid option: -${OPTARG}"
        get_help
        ;;
    esac
  done
  shift $((OPTIND -1))

  declare -grx CODE_SRC_DIR

  #  Remove the main command from the argument list.
  local -r _subcommand="${1:-}"
  if [[ -z ${_subcommand} ]]; then
    echo "Do some default thing."
    return 0
  fi

  shift
  case "${_subcommand}" in
    all)
      echo "Do something like run_all_something"
      exit 0
      ;;
    *)
      #  Unrecognized option, get help.
      echo "Invalid subcommand: ${_subcommand}!"
      get_help
      ;;
  esac

  return 0
}

function main() {
  get_opts "${@}"

  return 0
}
main "${@}"