Shell script utility to delete files in system

#!/bin/bash

 dialog --yesno "Do You wish to delete the files in your system" 7 60 \

 sel=$?

 case $sel in

0) ls;dialog --inputbox "Enter the file to delete" 7 60 2>input.txt;na=`cat input.txt`;rm $na ;dialog --msgbox "The file has been deleted successfully " 7 60 ;;

 1) dialog --msgbox "You have not entered the option " 7 60 ;;

 255) dialog --msgbox "You have pressed the ESC key " 7 60 ;;

esac