Monitor UNIX / Linux Server Disk Space with Shell Script

in Categories Monitoring last updated April 10, 2008

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

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  1. 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):

    + 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’
    ++ date
    + echo ‘Running out of space “/dev/vzfs (54%)” on as on Fri May 28 12:28:55 PDT 2010’
    + read output

    1. Hi,

      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.

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

  2. Hi there,

    Nice script. I modified it in the following way for my company

  3. what if your both partitions will run out of space? you will receive 2 mails. if you have more partitions, then you will receive more mails. how you do to receive all messages in one mail?

    1. You can modify script as follows:

  4. Thanks! I needed to change it to “df -HP” (Thanks, John Adams!), but then it worked fine. I incorporated it into an existing email notification script.

  5. I had a similar problem with a file system checker that I wrote.
    I found that if I did a “df -P” then the LVM filesystem output would be on a single line and I could parse it. It seems the LVM filesystem names can be rather large and end up on two lines, causing confusion to the grep command..

  6. Hello

    if I ran this script on my server it showed this error:
    ./diskspace: line 23: [: /dev/mapper/system-Xraid_5.4TB: integer expression expected
    ./diskspace: line 23: [: /xraid: integer expression expected

    Please any suggestion?


  7. hi vivik

    if this script is run on the system lvm eror occurred, example

    gareng:~ # df -h
    Filesystem Size Used Avail Use% Mounted on
    /dev/sda3 31G 2.6G 29G 9% /
    tmpfs 4.0G 8.0K 4.0G 1% /dev/shm
    /dev/sda1 134M 41M 93M 31% /boot
    274G 91G 183G 34% /u01
    20G 288M 19G 2% /home
    20G 6.6G 13G 35% /usr
    15G 35M 15G 1% /tmp
    /dev/sdc1 30G 15G 14G 52% /source
    /dev/sdc2 491G 162G 305G 35% /oradb

    i run scripts

    gareng:~ # sh line 11: [: /dev/mapper/vgu01-lvu01: integer expression expected line 11: [: /u01: integer expression expected line 11: [: /dev/mapper/vghome-lvhome: integer expression expected line 11: [: /home: integer expression expected line 11: [: /dev/mapper/vgusr-lvusr: integer expression expected line 11: [: /usr: integer expression expected line 11: [: /dev/mapper/vgtmp-lvtmp: integer expression expected line 11: [: /tmp: integer expression expected

    i need your help



  8. Magnificent script.

    I’ve seen that it has a little “bug”, because it throws an error because when doing the loop it finds a non numeric value due the header of the df command.

    To resolve it I added this command to the line
    grep / (that makes tot “grep” all that have the “/” symbols, that are relatet to volumens

    and the results is :
    df -H | grep / | grep -vE ‘^Filesystem|tmpfs|cdrom’ | awk ‘{ print $5 ” ” $1 }’

  9. I need help with this can anyone help
    1) Create a subdirectory in /tmp and move multiple file(s) specified in the script argument to that directory.
    2) Compress each of these files by calling a compression program.
    3) Move the file(s) back to the original directory (after checking if under the disk quota).
    4) Use a foreach loop to do this for each file one at a time.
    4) Perform error checking

  10. The script looks simple and nice… but how to do run it on redhat? do I just put on specific folder? Cron job? please let me know..

  11. Thanks for this excellent script !

    I would just perform a “df -HP” so it would be safer : -P for Posix display to avoid bugs with the awk.


  12. Excellent, thanks!

    I am trying to write one to monitor my Raid but having some issues with the regular expressions. Any ideas?


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