Shell argument parsing boilerplate

script.sh

#! /usr/bin/env bash

# Parse commands and options
while [[ $# -gt 0 ]]; do
  key="$1"

  case $key in
    # Boolean option
    -h|--help)
      _HELP=1
    ;;
    -v|--verbose)
      _VERBOSE=1
    ;;
    # Key value option
    -k|--key)
      _KEY=$2
      shift
    ;;
    *)
      # Save unmatched arguments
      _commands="$_commands $key"
    ;;
  esac
  shift || true
done

# Reset remaining, unmatched arguments
set -- $_commands

if [ "$_HELP" ]; then cat >&2 <<EOS
Usage: $0 [options] <arg1[, arg2, ...]>

Options:
  -h,--help    Show this help and exit
EOS
exit; fi

echo Verbose: $_VERBOSE
echo Key: $_KEY
echo Args: ${@}