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Monitor UNIX / Linux Server Disk Space with Shell Script

Shell script to monitor or watch the disk space and send an email alert if the (free avilable) percentage of space is >= 90%

  1. #!/bin/sh
  2. # Shell script to monitor or watch the disk space
  3. # It will send an email to $ADMIN, if the (free avilable) percentage
  4. # of space is >= 90%
  5. # -------------------------------------------------------------------------
  6. # Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
  7. # This script is licensed under GNU GPL version 2.0 or above
  8. # -------------------------------------------------------------------------
  9. # This script is part of nixCraft shell script collection (NSSC)
  10. # Visit http://bash.cyberciti.biz/ for more information.
  11. # ----------------------------------------------------------------------
  12. # Linux shell script to watch disk space (should work on other UNIX oses )
  13. # SEE URL: http://www.cyberciti.biz/tips/shell-script-to-watch-the-disk-space.html
  14. # set admin email so that you can get email
  15. ADMIN="me@somewher.com"
  16. # set alert level 90% is default
  17. ALERT=90
  18. df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $1 }' | while read output;
  19. do
  20. #echo $output
  21. usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
  22. partition=$(echo $output | awk '{ print $2 }' )
  23. if [ $usep -ge $ALERT ]; then
  24. echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" |
  25. mail -s "Alert: Almost out of disk space $usep" $ADMIN
  26. fi
  27. done

Comments on this entry are closed.

  • http://no erdenebat

    very good!! it’s my was finding script.

  • Bill

    Thanks for the LVM fixed, been searching about for that answer!

  • John Mathew


    I have the following script;

    # set alert level 90% is default
    df | grep -E “Filesystem|tmpfs|cdrom” | awk ‘{ print $5 ” ” $1 }’ | while read output;
    #echo $output
    usep=$(echo $output | awk ‘{ print $1}’ | cut -d’%’ -f1 )
    partition=$(echo $output | awk ‘{ print $2 }’ )
    if [ $usep -ge $ALERT ]; then
    echo “Running out of space \”$partition ($usep%)\” on $(hostname) as on $(date)” |
    mail -s “Alert: Almost out of disk space $usep” $ADMIN

    While I run the script it gives the following error, please help me. I have named the file as x.ksh and also let me know how to run the script.

  • charles

    this script seems to run but I never get an email. I tested with a simple email from the server and it came through fine. Here’s the output I get when I debug the script with bash -x (I’m a linux newbie):

    + ADMIN=me@mydomain.org
    + ALERT=20
    + df -H
    + grep /
    + grep -vE ‘^Filesystem|tmpfs|cdrom’
    + awk ‘{ print $5 ” ” $1 }’
    + read output
    ++ awk ‘{ print $1}’
    ++ cut -d% -f1
    ++ echo 54% /dev/vzfs
    + usep=54
    ++ echo 54% /dev/vzfs
    ++ awk ‘{ print $2 }’
    + partition=/dev/vzfs
    + ‘[‘ 54 -ge 20 ‘]’
    ++ hostname
    + mail -s ‘Alert: Almost out of disk space 54’ me@mydomain.org
    ++ date
    + echo ‘Running out of space “/dev/vzfs (54%)” on ip-72-XXX-XX-XYZ.ip.secureserver.net as on Fri May 28 12:28:55 PDT 2010’
    + read output

  • Charles

    Actually just found out it works fine. My email was down temporarily! Thanks!

  • UWAYO Jacques

    i get the below error what could be the problem

    but i dont receive anything
    # script to send simple email
    # email subject
    # Email To ?
    # Email text/message
    echo “This is an email message test”> $EMAILMESSAGE
    echo “This is email text” >>$EMAILMESSAGE
    # send an email using /bin/mail
    /bin/mail -s “$SUBJECT” “$EMAIL” < $EMAILMESSAGE

  • Ben

    you should also use the -P option of df “df -P -H”
    (-P for POSIX compatibility so you dont get into trouble when your diskname ist to long like /dev/mapper/VolGroup00-LogVol00)
    also df -i (for inodes) is highly recommended to use, because you easily forget to check for inodes if you have free space but cant create a file =)

  • nicole

    Hi, i’m a newbie, and i’ve been asked to create a script that will monitor different directories in different systems e.g.:

    /home of system1 – 60%
    /models of system2 – 70%
    /bikes of system3 – 80%

    and any of the above meet their respective threshold, will send an email to me
    informing that that particular directory is on limit.

    fyi, i have a server than can ssh to all of this directories/systems.

    hoping for your quick response.

  • Anonymous

    Thanks UWAYO.
    -P option worked with the script. Nice and simple script..

  • Anon

    I have tried the script and it does not appear to work.

    I set the limit to “35”, as I wanted to test it out and the highest percentage usage was 38%. I changed the E-Mail address to what I want to use and then ran the script. The script has not sent me an E-Mail after 10 minutes of running it.

    I tried the “-P” that was mentioned in several comments without luck.

    The server that this script is currently running on is a basic Ubuntu 9.04 server and has only had SSH installed.

  • Dinesh


    I am new to scripting.
    I have run this and working perfectly.
    Just want 2 modifications.

    If i want to check for more than one server using same script.
    And i want single mail instead of many.

    Please Help. :)

  • d0rk

    you cannot run this with sh … you need bash as it is a BASH script.

  • d0rk

    you are using the korn shell, which has many differences from bash. first off, to use parameter substitution in that shell you need:

    echo -e "string with backslash \n"
  • Andre


    Right now, I have setup a cronjob to run this script hourly.
    Does anyone know how to stop the email to be sent out if the previous quota level is the same as the current one?

    i.e.: An email is sent once it hits the 95% threshold; however at the next hour if the level is still at 95%, no email is sent till it hits 96% or more.

  • Andre

    Just answered my own question after a few days of figuring out bash regex. Are there any other more elegant ways?

    # set alert level 95% is default
    # The current variable takes from a file which gives the prior saved value of usage
    current=`cat /tmp/currentUsage`

    df -PH | grep -vE ‘^Filesystem|tmpfs|cdrom’ | awk ‘{ print $5 ” ” $1 }’ | while read output;
    usep=$(echo $output | awk ‘{ print $1}’ | cut -d’%’ -f1)
    partition=$(echo $output | awk ‘{ print $2 }’ )

    # If current usage is greater than ALERT and is greater the prior value then send a mail.

    if [ $usep -ge $ALERT ] && [ $usep -gt $current ]; then
    echo “Running out of space \”$partition ($usep%)\” on $(hostname) as on $(date)” |
    mail -s “Alert: Almost out of disk space $partition $usep%” $ADMIN

    # establish the new current value
    echo $output | awk ‘{ print $1}’ | cut -d’%’ -f1 > /tmp/currentUsage

  • KC

    Thanks, VIVEK and BEN. Very nice script and the quick correction, thanks a lot.

  • http://yamara.net/ Yamaranews

    Its very helful
    Thank you

  • Scriptiee

    Brilliant little script, will put it to good use! Thanks guys

  • Leszek


    Thanks for the script. It’s doing it’s job nicely but I’m a little surprised nobody complained about an error it returns if You don’t cut off the first line of df output:

    ./monitor.sh: 22: [: Illegal number: dost.

    I had to change line 19 to:

    df -H | grep -vE ‘^Filesystem|tmpfs|cdrom’ | tail -n+2 | awk ‘{ print $5 ” ” $1 }’ | while read output;

  • omprakash

    i want 5 mail alert instead of many alert when disk space reached max limit .