Simple Shell Script for Disk Space Notification

1. Create a file /home/diskspace.sh

2. Enter the following code in the script

=============================
#!/bin/sh

#Threshold is set to 70 here.
THRESHOLD=70
MAILTO=”youremailaddress”
TEMPFILE=/tmp/diskspace.temp
HOSTNAME=`hostname`

rm -f $TEMPFILE

#Calculate the Current Disk Usage with the below command.
CDU=$(df -h | tail -1 | awk ‘{print $5}’ | sed ‘s/%//’)

#Compare the current value with the threshold one.
if [ $(expr $CDU ">=" $THRESHOLD) -ne 0 ]
then
echo “Warning!!! Disk Space usage on server $HOSTNAME is ${CDU}%” >> $TEMPFILE
fi

#Send an email if /tmp/diskspace.temp is present.
if [ -e $TEMPFILE ]
then
mail -s “Disk Space Notification” $MAILTO < $TEMPFILE
fi

rm -f $TEMPFILE
==============================

3. Save the file and execute using crontab

crontab -e

0 1 * * 0  /bin/sh  /home/diskspace.sh