#!/bin/bash

while true

do

AVAILABE=`df -TH | grep /dev/sda3 | awk '{ print $6 }' | cut -d "%" -f1`

if [ $AVAILABE -ge 80 ]

then

    echo "Hard Disk Usage is: %$AVAILABE" |mail -s "Disk Usage Alert" root@localhost

fi

sleep 10

done