Published November 16, 2018 by

Send an Email Alert When System Disk Space Gets Low

Step 1: Get Disk Space

 df -h  

Step 2: Next filter out file system and find out the percentage of space

 (df / | grep / | awk '{ print $5}' | sed 's/%//g')  

Step 3: Write a shell script

If you don't want to step up to a full monitoring solution such as Nagios you can create your own scripts for monitoring the things that you want to monitor, such as disk space. The following script alerts you when your root partition is almost full.

 CURRENT=$(df / | grep / | awk '{ print $5}' | sed 's/%//g')  
 if [ "$CURRENT" -gt "$THRESHOLD" ] ; then  
   mail -s 'Disk Space Alert' << EOF  
 Your root partition remaining free space is critically low. Used: $CURRENT%  
The script sends an email when the disk usage rises above the percentage specified by the THRESHOLD variable (90% here).

To run it daily, for example, save the script to the file in /opt directory, change the email to your email, and add the following line at the end of /etc/crontab file.

 @daily /opt/