Example of a basic menu driven program in bash

menu.sh

#!/bin/bash

function p
{
  echo $@
}

function displayMenu
{
  p ""
  p "1) Start"
  p "2) Stop"
  p "3) Quit"
  p ""
  p -n "Enter selection: "
}

function startProg
{
  p "Starting..."
}

function stopProg
{
  p "Stopping..."
}

function quitProg
{
  p "Bye, bye"
  exit 0
}

function processInput
{
  case "$1" in
    1) startProg ;;
    2) stopProg ;;
    3) quitProg ;;
    *) ;;
  esac
}

#Main
while [ 0 -lt 1 ]; do
  displayMenu
  read input
  processInput $input
done