check_disk_space.sh

#!/bin/bash
#reference - stolen from https://www.cyberciti.biz/tips/shell-script-to-watch-the-disk-space.html
#This script should run on any Linux host and has no hard coded parameters
#set percentage to trigger alert
threshold=80
emailaddress=youremail@yourdomain.com
#important****the first line will exclude filesystems with specified strings******
df -PH | grep -vE '^Filesystem|tmpfs|cdrom|nashome' | awk '{ print $5 " " $1 " " $6 }' | while read output;
do
  echo $output
  usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1  )
  partition=$(echo $output | awk '{ print $2 }' )
  mount=$(echo $output | awk '{ print $3 }' )
  if [ $usep -ge $threshold ]; then
    echo -e \
	"Running low on space \"$partition ($usep%)\" on $(hostname) as on $(date). " \
	"It is mounted at $mount. \n\n " \
	"To find large directories in the mount use the disk usage command, i.e. - du -ax $mount | sort -n -r | head -n 10 \n\n " \
	"**This email was generated from a script run on $(hostname)**"| \
     mailx -s "Alert: Low disk space $usep% on $(hostname)" $emailaddress
  fi
done