systemcheck.sh

#!/bin/bash

CONTINUE=true

main_menu () {
   echo "Enter the letter for one of the following options:"
   echo "1. Display today's date and time."
   echo "2. Display first 5 lines of top command's output."
   echo "3. Display a list of who is logged in."
   echo "4. Display disk usage for /home/admin in human readable format."
   echo "5. Display file system usage in human readable format."
   echo "0. Exit."

   echo ""

   read MENU_OPTION

   echo ""
}

execute_option () {
   if [ $MENU_OPTION = 1 ]; then
      date
   elif [ $MENU_OPTION = 2 ]; then
      top -n1 -w80 >> top.txt
      head -5 top.txt
      rm top.txt
   elif [ $MENU_OPTION = 3 ]; then
      who
   elif [ $MENU_OPTION = 4 ]; then
      sudo du -h /home/admin
   elif [ $MENU_OPTION = 5 ]; then
      sudo df -h
   elif [ $MENU_OPTION = 0 ]; then
      CONTINUE=false
   else
      $MENU_OPTION is invalid.
   fi
}

while [ $CONTINUE = true ]; do
   echo ""
   main_menu
   execute_option
done