multi select bash

multiselect.sh

#!/bin/bash

function multiselect {
	# little helpers for terminal print control and key input
	ESC=$( printf "\033")
	cursor_blink_on()   { printf "$ESC[?25h"; }
	cursor_blink_off()  { printf "$ESC[?25l"; }
	cursor_to()         { printf "$ESC[$1;${2:-1}H"; }
	print_inactive()    { printf "$2   $1 "; }
	print_active()      { printf "$2  $ESC[7m $1 $ESC[27m"; }
	get_cursor_row()    { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }

	local return_value=$1
	local -n options=$2
	local -n defaults=$3

	local selected=()
	for ((i=0; i<${#options[@]}; i++)); do
		if [[ ${defaults[i]} = "true" ]]; then
			selected+=("true")
		else
			selected+=("false")
		fi
		printf "\n"
	done

	# determine current screen position for overwriting the options
	local lastrow=`get_cursor_row`
	local startrow=$(($lastrow - ${#options[@]}))

	# ensure cursor and input echoing back on upon a ctrl+c during read -s
	trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
	cursor_blink_off

	key_input() {
		local key
		IFS= read -rsn1 key 2>/dev/null >&2
		if [[ $key = ""      ]]; then echo enter; fi;
		if [[ $key = $'\x20' ]]; then echo space; fi;
		if [[ $key = "k" ]]; then echo up; fi;
		if [[ $key = "j" ]]; then echo down; fi;
		if [[ $key = $'\x1b' ]]; then
			read -rsn2 key
			if [[ $key = [A || $key = k ]]; then echo up;    fi;
			if [[ $key = [B || $key = j ]]; then echo down;  fi;
		fi 
	}

	toggle_option() {
		local option=$1
		if [[ ${selected[option]} == true ]]; then
			selected[option]=false
		else
			selected[option]=true
		fi
	}

	print_options() {
		# print options by overwriting the last lines
		local idx=0
		for option in "${options[@]}"; do
			local prefix="[ ]"
			if [[ ${selected[idx]} == true ]]; then
			  prefix="[\e[38;5;46m✔\e[0m]"
			fi

			cursor_to $(($startrow + $idx))
			if [ $idx -eq $1 ]; then
				print_active "$option" "$prefix"
			else
				print_inactive "$option" "$prefix"
			fi
			((idx++))
		done
	}

	local active=0
	while true; do
		print_options $active

		# user key control
		case `key_input` in
			space)  toggle_option $active;;
			enter)  print_options -1; break;;
			up)     ((active--));
					if [ $active -lt 0 ]; then active=$((${#options[@]} - 1)); fi;;
			down)   ((active++));
					if [ $active -ge ${#options[@]} ]; then active=0; fi;;
		esac
	done

	# cursor position back to normal
	cursor_to $lastrow
	printf "\n"
	cursor_blink_on

	# eval $return_value='("${selected[@]}")'

	local values=()
	for ((i=0; i<${#options[@]}; i++)); do
		option=${options[$i]}
		if [[ ${selected[$i]} == true ]]; then
			values+=($option)
		fi
	done
  eval $return_value='("${values[@]}")'
}

usage.sh

#!/usr/bin/env bash

source=("one" "two" "three" "four")
default_selected=("two" "four")
multiselect selected_options source default_selected

for selected_option in "${selected_options[@]}"; do
  echo "you selected: $selected_option"
done