menu control with bash

menu.sh

#! /bin/bash


NC='\033[0m' # No Color
L_GREEN='\033[1;32m'
L_RED='\033[1;31m'
B_YELLOW='\033[1;39;43m'

# move one key up: \r\e[1A

menu=("Line 1" "Line 2" "Line 3" "Line 4" "Line 5")
highlight_menu=("0" "0" "0" "0" "0")

for i in $(seq 0 $(( ${#menu[@]} - 1)))
do
  echo "${menu[$i]}"
done

cursor_pos=${#menu[@]}

while true
do
  read -s -n 1 -t 0.1 input               # so read doesn't hang
  if [[ $input == "w" &&  $cursor_pos -gt 0 ]]; then
    if [[ ${highlight_menu[$cursor_pos]} == "0" ]]; then
        echo -ne "\r$NC${menu[$cursor_pos]}$NC"
    else
        echo -ne "\r$B_YELLOW${menu[$cursor_pos]}$NC"
    fi
    echo -ne "\r\e[1A"
    cursor_pos=$(( $cursor_pos - 1))
    if [[ ${highlight_menu[$cursor_pos]} == "1" ]]; then
        echo -ne "\r$B_YELLOW$L_RED${menu[$cursor_pos]}$NC"
    else
        echo -ne "\r$NC$L_RED${menu[$cursor_pos]}$NC"
    fi
  fi
  if [[ $input == "s" && $cursor_pos -lt ${#menu[@]} ]]; then
      if [[ ${highlight_menu[$cursor_pos]} == "0" ]]; then
        echo -ne "\r$NC${menu[$cursor_pos]}$NC"
      else
        echo -ne "\r$B_YELLOW${menu[$cursor_pos]}$NC"
      fi 
      echo -ne "\r\e[1B"
      cursor_pos=$(( $cursor_pos + 1))
      if [[ ${highlight_menu[$cursor_pos]} == "1" ]]; then
        echo -ne "$B_YELLOW$L_RED${menu[$cursor_pos]}$NC"
      else
        echo -ne "$NC$L_RED${menu[$cursor_pos]}$NC"
      fi
  fi
  if [[ $input = "f" ]]; then
     echo "${menu[$cursor_pos]}" > /tmp/session.output
  fi
  if [[ $input = "q" ]]; then
     rm -f /tmp/session.output
     pkill screen
  fi
  if [[ $input = "1" ]]; then
    if [[  ${highlight_menu[$cursor_pos]} == "0" ]]; then
        echo -ne "\r$B_YELLOW${menu[$cursor_pos]}$NC"
        highlight_menu[$cursor_pos]="1"
    else
        echo -ne "\r$NC${menu[$cursor_pos]}$NC"
        highlight_menu[$cursor_pos]="0"
    fi
  fi  
done