シェルスクリプトでチェックボックス式の選択メニューを作る

#!/bin/bash#メニュー
options[0]="option 1"
options[1]="option 2"
options[2]="option 3"
options[3]="option 4"
options[4]="option 5"#各メニューごとに挙動を記述するfunction DOIT {if[[${choices[0]}]];then
        echo"Option 1 selected"fi

    if[[${choices[1]}]];then
        echo"Option 2 selected"fi

    if[[${choices[2]}]];then
        echo"Option 3 selected"fi

    if[[${choices[3]}]];then
        echo"Option 4 selected"fi

    if[[${choices[4]}]];then
        echo"Option 5 selected"fi}

clear

#現在フォーカスしているメニューcurrent_line=0

#メニュー一覧を表示function MENU {echo"移動:[↑]or[↓], 選択:[SPACE], 決定:[ENTER]"for NUM in${!options[@]};do
        if[$NUM-eq$current_line];then
            echo-n">"else
            echo-n" "fi
        echo"[${choices[NUM]:-}]"":${options[NUM]}"done}#メニュー選択のループfunction SELECT_LOOP {while true;do
        while MENU &&IFS=read-r-n1-s SELECTION &&[[-n"$SELECTION"]];do
            if[[$SELECTION==$'\x1b']];then
                read-r-n2-s rest
                SELECTION+="$rest"fi  
            clear

            case$SELECTIONin$'\x1b\x5b\x41')#up arrowif[[$current_line-ne 0 ]];then
                        current_line=$(( current_line -1))else
                        current_line=$((${#options[@]}-1))fi;;$'\x1b\x5b\x42')#down arrowif[[$current_line-ne$((${#options[@]}-1))]];then
                        current_line=$(( current_line +1))else
                        current_line=0
                    fi;;$'\x20')#spaceif[["${choices[current_line]}"=="+"]];then
                        choices[current_line]=""else
                        choices[current_line]="+"fi;;esacdone

        read-p"選べた? [Y/n]" Answer
        case$Answerin''|[Yy]*)break;;;[Nn]*);;*)echo"YES or NOで答えてね";;esac
        clear
    done}

SELECT_LOOP
DOIT