arg_parse_example

#!/bin/sh

#abort on error
set -e

function usage
{
    echo "usage: arg_parse_example -a AN_ARG -s SOME_MORE_ARGS [-y YET_MORE_ARGS || -h]"
    echo "   ";
    echo "  -a | --an_arg            : A super special argument";
    echo "  -s | --some_more_args    : Another argument";
    echo "  -y | --yet_more_args     : An optional argument";
    echo "  -h | --help              : This message";
}

function parse_args
{
  # positional args
  args=()

  # named args
  while [ "$1" != "" ]; do
      case "$1" in
          -a | --an_arg )               an_arg="$2";             shift;;
          -s | --some_more_args )       some_more_args="$2";     shift;;
          -y | --yet_more_args )        yet_more_args="$2";      shift;;
          -h | --help )                 usage;                   exit;; # quit and show usage
          * )                           args+=("$1")             # if no match, add it to the positional args
      esac
      shift # move to next kv pair
  done

  # restore positional args
  set -- "${args[@]}"

  # set positionals to vars
  positional_1="${args[0]}"
  positional_2="${args[1]}"

  # validate required args
  if [[ -z "${an_arg}" || -z "${some_more_args}" ]]; then
      echo "Invalid arguments"
      usage
      exit;
  fi

  # set defaults
  if [[ -z "$yet_more_args" ]]; then
      yet_more_args="a default value";
  fi
}


function run
{
  parse_args "$@"

  echo "you passed in...\n"
  echo "positional arg 1: $positional_1"
  echo "positional arg 2: $positional_2"

  echo "named arg: an_arg: $an_arg"
  echo "named arg: some_more_args: $some_more_args"
  echo "named arg: yet_more_args: $yet_more_args"
}



run "$@";