Bash monitor disk usage

Question

I bought a NAS box which has a cut down version of debian on it.

It ran out of space the other day and I did not realise. I am basically wanting to write a bash script that will alert me whenever the disk gets over 90% full.

Is anyone aware of a script that will do this or give me some advice on writing one?

Answer 1

#!/bin/bash
source /etc/profile

# Device to check
devname="/dev/sdb1"

let p=`df -k $devname | grep -v ^File | awk '{printf ("%i",$3*100 / $2); }'`
if [ $p -ge 90 ]
then
  df -h $devname | mail -s "Low on space" my@email.com
fi

Crontab this to run however often you want an alert

EDIT: For multiple disks

#!/bin/bash
source /etc/profile

# Devices to check
devnames="/dev/sdb1 /dev/sda1"

for devname in $devnames
do
  let p=`df -k $devname | grep -v ^File | awk '{printf ("%i",$3*100 / $2); }'`
  if [ $p -ge 90 ]
  then
    df -h $devname | mail -s "$devname is low on space" my@email.com
  fi
done