シェルスクリプトで上下左右キーを検知する

select.sh

#!/usr/bin/env bash

while IFS= read -r -n1 -s SELECTION && [[ -n "$SELECTION" ]]; do
    if [[ $SELECTION == $'\x1b' ]]; then
        read -r -n2 -s rest
        SELECTION+="$rest"
    fi	

    case $SELECTION in
        $'\x1b\x5b\x41') #up arrow
            echo "上"
            ;;
        $'\x1b\x5b\x42') #down arrow
            echo "下"
            ;;
        $'\x1b\x5b\x43') #right arrow
            echo "右"
            ;;
        $'\x1b\x5b\x44') #left arrow
            echo "左"
            ;;
        $'\x20') #space
            echo "スペース"
            ;;
    esac
done

参考
https://gist.github.com/shinyaoguri/782adf1c6765dba0717745578aa9c85f