#!/bin/bash

LIMIT='80'

#Here we declare variable LIMIT with max of used space

DIR="( $(df -Ph | column -t | awk '{print $6}' | grep -v Mounted) )"   -------- here everything is saving as single variable as the output is a 5th column; but i need that to be processed line by line in the below for loop.

#Here we declare variable DIR with name of directory

MAILTO=' xyxz@abc.com'

#Here we declare variable MAILTO with email address

SUBJECT="$DIR disk usage"

#Here we declare variable SUBJECT with subject of email

MAILX='mailx'

#Here we declare variable MAILX with mailx command that will send email

which $MAILX > /dev/null 2>&1

#Here we check if mailx command exist

if ! [ $? -eq 0 ]

#We check exit status of previous command if exit status not 0 this mean that mailx is not installed on system

then

          echo "Please install $MAILX"

#Here we warn user that mailx not installed

          exit 1

#Here we will exit from script

fi

#To check real used size, we need to navigate to folder
for i in $DIR 
do
USED=$(df -Ph $i | awk '{print $5}' | sed -ne 2p | cut -d"%" -f1)
done

#This line will get used space of partition where we currently, this will use df command, and get used space in %, and after cut % from value.

if [ "$USED" -gt "$LIMIT" ]

#If used space is bigger than LIMIT

then

      sudo du -sh ${DIR}/* | $MAILX -s "$SUBJECT" "$MAILTO"

#This will print space usage by each directory inside directory $DIR, and after MAILX will send email with SUBJECT to MAILTO

fi