#!/bin/bash  
 CURRENT=$(df -h | awk '{ print $5}' | sed 's/%//g')  
 THRESHOLD=30  
   
 if [ "$CURRENT" -gt "$THRESHOLD" ] ; then  
   mail -s 'Disk Space Alert' anthony@cbinet.net << EOF  
 Your root partition remaining free space is critically low. Used: $CURRENT%  
 EOF  
 fi