Shell Programming and Scripting

-------------------------------------
            Main Menu
-------------------------------------
[1] Option 1
[2] Option 2
[3] Option 3
[4] Option 4
[5] Exit
=====================================
Enter your menu choice [1-5]:

-------------------------------------
            Main Menu
-------------------------------------
[1] Option 1
[2] Option 2
[3] Option 3
[4] Option 4
[5] Exit
=====================================
Enter your menu choice [1-5] [Default :1]:

#!/usr/bin/bash

# Menu Item

main_menu()
{

while :
do
	clear
	echo " "
	echo "-------------------------------------"
	echo "            Main Menu "
	echo "-------------------------------------"
	echo "[1] Option 1"
	echo "[2] Option 2"
	echo "[3] Option 3"
	echo "[4] Option 4"
	echo "[5] Exit"
	echo "====================================="
	echo "Enter your menu choice [1-5]: \c "
	read m_menu
	
	case "$m_menu" in

		1) option_1;;
		2) option_2;;
		3) option_3;;
		4) option_4;;
		5) exit 0;;
		*) echo "\nOpps!!! Please Select Correct Choice";
		   echo "Press ENTER To Continue..." ; read ;;
	esac
done
}

option_1()
{
  echo "option 1"
  echo "\nPress ENTER To Continue..."
    read
	return
}

option_2()
{
	echo "option 2"
	echo "\nPress ENTER To Continue..."
    read
	return
}

option_3()
{
	echo "option 3"
	echo "\nPress ENTER To Continue..."
    read
	return
}

option_4()
{
	echo "option 4"
	echo "\nPress ENTER To Continue..."
    read
	return
}

main_menu

"") option_1;;

exec 3>&1
RESULT=$(dialog --menu "Main Menu" 10 80 8 \
    1 "Option 1" \
    2 "Option 2" \
    3 "Option 3" \
        2>&1 >&3)
exec 3>&-

case "$RESULT" in 
 ...
esac