Simple Shell Flag Parsing

flags.sh

#!/bin/bash

set -e

declare -A options
options["your"]=false
options["options"]=false 
options["here"]=false 

main () {
  parse_options "$@"

  for option in ${!options[@]}; do
    echo $option ${options[$option]}
  done
}

parse_options () {
  local args=( "$@" )

  for option in ${!options[@]}; do
    for index in ${!args[@]}; do
      local flag=${args[$index]}
      if [ "$flag" = "--$option" ]; then
        local next="${args[$index + 1]}"
        if [[ $next == "" ]] || [[ $next =~ ^--.* ]]; then
          options[$option]=true
        else
          options[$option]=$next
        fi
      fi
    done
  done
}

main "$@"

./flags.sh --your "a lunatic" --here

prints:

your a lunatic
options false
here true