Send email to when disk is below a limit

email-when-disk-is-below-limit.sh

#!/bin/sh

#The limit is 30% now
limit=10
mail=contact@debian-tutorials.com
tmp_file=/tmp/diskusage
hostname=`hostname`

#Now the script will calculate the current disk usage
disk=$(df -h | awk 'FNR == 2 {print $5}' | sed 's/%//')

#Now the script will compare the current value with the limit
if [ $(expr $disk ">=" $limit) -ne 0 ]
then

echo "Your Disk space limit is set to: $limit %" > $tmp_file
echo "Occupied space on the server is: $disk %" >> $tmp_file
echo "Notification!!! Disk Space Usage on server $hostname exceeded the limit." >> $tmp_file
fi

#Now we send the notification
if [ -e $TEMPFILE ]
then
mail -s "IMPORTANT!!! Disk Space Notification" $mail < $tmp_file
fi
exit 0