dell 1501As many other Ubuntu users several days ago I’ve upgraded my Feisty to Gutsy at my Dell Inspiron 1501.

Unfortunately many things that worked for me in Feisty doesn’t work in Gutsy just after upgrading. Among them are: suspend/hibernate and brightness adjustment. At this moment I’m trying to get these features working and certainly share results here but not workable brightness adjustment really disturbed me. So, until I didn’t find a solution how to adjust LCD brightness with keyboard, there is nice workaround: execute the following command with root rights (sudo -s to get it):

echo -n 100 > /proc/acpi/video/VGA/LCD/brightness

This will make you LCD screen as bright as possible and you can proceed with your work (like me 🙂 ). To lower brightness just replace 100 with another value like 62 and watch the results.

Hope it helps!

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  3. October 27, 2007  6:58 am by vivek Reply

    Nice tip :)

  4. Pingback : dell » Ajust LCD brightness from command line (works at Dell 1501)

  5. November 11, 2007  7:27 am by aruvoski Reply


  6. November 12, 2007  9:06 am by admin Reply

    Hi aruvoski,

    In your Ubuntu:
    Applications -> Accessories -> Terminal

    Then type `sudo -s` and enter your password. After you've got prompt like ~#, you can type:

    echo -n 100 > /proc/acpi/video/VGA/LCD/brightness
    to adjust LCD brightness where 100 is maximum value and 62 is minimum.

    Hope it helps! :)

    P.S. You're welcome to ask any related questions here ;)

  7. January 10, 2008  3:34 pm by Cristian Navalici Reply

    Pay attention that you might have GLX instead of VGA as in:


    Anyway, this is a 'cool' tip. Thanks for it!

  8. January 10, 2008  7:25 pm by Jillian Reply

    oh good lord THANK YOU

    i have been trying to figure this out for weeks.


  9. January 10, 2008  9:50 pm by admin Reply

    Hey everybody, thanks for your comments! :)

  10. January 24, 2008  3:56 pm by Rasha Reply

    I have a Dell Latitude C610 and I've tried running the line in Ubuntu tho I had to modify as my line is /proc/acpi/video/VID/LCD/brightness. But it's saying the command is unknown.

  11. January 24, 2008  8:28 pm by admin Reply

    Hello Rasha,

    try this:

    <code>sudo -s</code> or <code>su</code>


    <code>echo -n 100 > /proc/acpi/video/VID/LCD/brightness</code>


  12. February 6, 2008  6:55 am by Satish Vellanki Reply

    No luck for me :-(

    # echo -n 50 > /proc/acpi/video/VGA/LCD/brightness

    bash: echo: write error: Invalid argument

    What could be wrong?

  13. February 18, 2008  6:01 pm by ross Reply

    turn off acpi and it will work with fn keys

  14. February 18, 2008  6:02 pm by ross Reply

    it might only work on opensuse. when you do this kpowersave doesnt work

  15. February 23, 2008  5:57 pm by animatt Reply

    Try running cat /proc/acpi/video/VGA/LCD/brightness

    This will show supported brightness levels.

    Running it on my monitor gives

    root@Gateway-M-Series:/home/animatt# cat /proc/acpi/video/VGA/LCD/brightnesslevels: 100 37 12 25 37 50 62 75 87 100

    current: 12

  16. March 3, 2008  4:04 am by Alex Reply

    Thanks for posting this info. Every day, I learn something new about using linux. Much more fun than M$ Win!

    Seems to me this could easily be put in a script that would read the current setting and go up or down depending on which name it was called with.

    I'm going to work on it for myself and post it back here in case anyone else is interested.

    Can all of the hardware be controlled via the /proc dir?

    Thanks again for the pointer. :-)

  17. March 4, 2008  4:14 am by Alex Reply

    The following is working nicely for me:


    # adjust lcd brightness on Dell Inspiron 1501 - 080303 Alex P Janssen Jr -


    # Save this script to a file named in /home/yourusername/bin

    # Make it executable: chmod +x

    # Save yourself having to run it in a terminal and enter your password each time

    # edit sudoers: sudo visudo

    # add to sudoers: yourusername ALL=(ALL) NOPASSWD:/bin/bash

    # save and exit

    # link brightup and brightdn to

    # ln -s /home/yourusername/bin/ /home/yourusername/bin/brightup

    # ln -s /home/yourusername/bin/ /home/yourusername/bin/brightdn

    # Add a couple of custum launchers to your panel ( I run Gnome )

    # Right-click the panel and select Add to Panel

    # Click Custom Launcher

    # Type=Application, Name=Darker, Command=sudo bash -c /home/apjjr/bin/brightdn

    # Select a down-arrow for an icon and Close

    # Do the same for brightup, except set the name to Lighter and pick an up-arrow


    # check our id

    #echo `id`


    ourname=`basename "$ourname"`

    xx=`cat /proc/acpi/video/VGA/LCD/brightness | grep current | cut -c 9-`

    curbright=`echo $xx`

    # check process name and current brightness setting

    #echo "${ourname},${curbright}:"

    case $curbright in

    0) # after boot my brightness value is 0

    # echo "12"

    echo -n 12 >/proc/acpi/video/VGA/LCD/brightness


    12) if [ "$ourname" = "brightup" ]; then

    #echo "12 to 25"

    echo -n 25 >/proc/acpi/video/VGA/LCD/brightness



    25) if [ "$ourname" = "brightup" ]; then

    #echo "25 to 37"

    echo -n 37 >/proc/acpi/video/VGA/LCD/brightness


    echo -n 12 >/proc/acpi/video/VGA/LCD/brightness



    37) if [ "$ourname" = "brightup" ]; then

    #echo "37 to 50"

    echo -n 50 >/proc/acpi/video/VGA/LCD/brightness


    echo -n 25 >/proc/acpi/video/VGA/LCD/brightness



    50) if [ "$ourname" = "brightup" ]; then

    #echo "50 to 62"

    echo -n 62 >/proc/acpi/video/VGA/LCD/brightness


    echo -n 37 >/proc/acpi/video/VGA/LCD/brightness



    62) if [ "$ourname" = "brightup" ]; then

    #echo "62 to 75"

    echo -n 75 >/proc/acpi/video/VGA/LCD/brightness


    echo -n 50 >/proc/acpi/video/VGA/LCD/brightness



    75) if [ "$ourname" = "brightup" ]; then

    #echo "75 to 87"

    echo -n 87 >/proc/acpi/video/VGA/LCD/brightness


    echo -n 62 >/proc/acpi/video/VGA/LCD/brightness



    87) if [ "$ourname" = "brightup" ]; then

    #echo "87 to 100"

    echo -n 100 >/proc/acpi/video/VGA/LCD/brightness


    echo -n 75 >/proc/acpi/video/VGA/LCD/brightness



    100) if [ "$ourname" != "brightup" ]; then

    echo -n 87 >/proc/acpi/video/VGA/LCD/brightness




    exit 0

    That's it.


  18. May 31, 2008  9:11 am by Petko Reply

    Hello. Here is another way to do this. I add in the file ~/.bashrc :

    Bup ()



    current=`cat $FILE | grep current | cut -c 10-`


    for i in `cat $FILE | grep levels | cut -c 17-`; do

    if [[ $i -eq $current && "$1" == "-" ]]; then

    echo -n $prev > $FILE


    elif [ $i -gt $current ]; then

    echo -n $i > $FILE ;






    Bdown (){ Bup -; }

    (Just make sure the line FILE=/proc/acpi/video/... points to your correct file.)

    This way, I can type in a terminal "Bup" or "Bdown" to set the brightness up or down.


  19. October 17, 2008  12:23 pm by Geoffroy Reply


    This has worked for me in the directory, for me
    and I did the command
    echo -n 100> brightness
    in my directory.
    Don't forget to change the rights and owner for the file brightness

    Thanks for this admin:
    " echo -n 100 > /proc/acpi/video/VGA/LCD/brightness
    to adjust LCD brightness where 100 is maximum value and 62 is minimum.
    Hope it helps! :)"

  20. December 26, 2008  11:21 am by Ohnoesmilk Reply

    thank you so much!!! you saved my eyes from burning! :D

  21. March 1, 2009  1:55 pm by Radha Reply

    guys do this work on windows?

    i need to know pls make me know the fast you can my email is

  22. October 14, 2009  2:35 am by Dan Reply

    Is there anyway to control the brightness on an LCD panel monitor for a desktop. Mine is too bright and there is no video folder. I'm sure this is possible as when the computer is left idle it gradually dims until it goes blank. There must be a way to dim the screen a set amount.

  23. November 6, 2009  9:52 pm by ???????? ????? Reply

    ??? ??? ??????? ????????? ?? ????. ??? ???????? ?????? ??????????????.

  24. November 29, 2009  12:27 pm by Benneh Reply

    Hi Neal Stephenson!

    I use Kubuntu 8.04 and the following is working nicely for me:

    sudo su

    and next:

    echo -n 100 > /proc/acpi/video/VGA/LCD/brightness

    Hope it helps!

  25. November 30, 2009  4:32 pm by Tyrone Dimery Reply

    Hello, I just found your website while searching around online as I'm seeking some information on LCD TVs!. It's a very interesting site so I bookmarked your site and intend to return tomorrow to enjoy a more detailed look when I have more time.

  26. December 19, 2009  1:38 am by RProgrammer Reply

    I have GFX0 instead of VGA on Karmic and I get the Invalid Argument error too.

    /proc/acpi/video/GFX0/LCD# echo -n 100 > brightness

    bash: echo: write error: Invalid argument

    /proc/acpi/video/GFX0/LCD# cat brightness


  27. December 19, 2009  1:42 am by RProgrammer Reply

    Sorry, the forum ate my <> signs

    /proc/acpi/video/GFX0/LCD# cat brightness

    <not supported>


  28. January 17, 2010  2:29 am by ?e??????a Reply

    ??? ???????? ???????????????, ?? ??? ??????? ??? ?? ???????????? ????? ???????? ?????? ????? ?????-?? ?????.

  29. February 24, 2010  12:05 pm by Anaconda Reply

    for all of you, who have the "invalid argument" problem. And who can't change the brightnes value, because you are unable to edit the brightness file.

    Install xbacklight (eg. sudo apt-get install xbacklight) and use it to change the brightness value eg.
    xbacklight -set 100

    Just change the 100 to anything you want between 0-100
    In my machine the numbers are not in logical order, but once you know how bright each seting is you can "remember those numbers", or write a script

    And xbacklight does change the brightness value too...

  30. February 25, 2010  4:03 am by nomad Reply

    i installed xbacklight and typed in "xbacklight -set 100"
    then it says "No outputs have backlight property"

    what's the problem..??

  31. April 20, 2010  8:59 pm by Nevyn Reply

    Hi Guys,

    Okay - those guys having problems... Type in:

    cat /procacpi/video/VGA/LCD/brightness

    In that above line, LCD may be something different - mines LLCD. Anyway, there's the possibility that yours isn't on a scale from 0 to 100. Mine goes from 0 to 15. So if you're looking at your monitor and it's already pretty bright, and you've run that command above, that's probably going to be your maximum value.

    So go to the original command, and alter your values to match.



  32. April 30, 2010  6:07 am by raff Reply

    i keep getting "bash: /proc/acpi/video/GLX0/LCD/brightness: No such file or directory"

    but it is there, i checked by browsing the file system, but the file is read-only

    anything i can do?

  33. April 30, 2010  8:08 pm by Ismas Reply

    One note: If you don't have /proc/acpi/video, do this:

    sudo modprobe video

    Now you have. :)

  34. June 15, 2010  5:39 pm by kanna Reply


    I am also getting “No outputs have backlight property”.

    After installing back light. What should i do??

  35. September 22, 2010  4:07 pm by prakash Reply

    hey i am sing ubuntu 10.04 version. my system brightness is not changing with Fn key.
    /proc/acpi/video/VGA/LCD/brightness is not there. there is /proc/acpi/video/GFX0/DD01/brightness file. but when i followed with echo -n /proc/acpi/video/GFX0/DD01/brightness it is saying that echo is invalid arguement... please help me .. i am facing problem to my eyes with high brightness.

  36. September 30, 2010  4:28 am by Sergey Shlykovich Reply

    If you use gnome, you could just add Brightness Applet to you Panel

  37. November 16, 2010  3:30 pm by Agilar Reply

    Thanks - it works!

  38. December 9, 2010  3:21 am by Iklswt Reply

    Thank you for shfwaring youwr admin would get ready a severely beneficial write-up I congratulate.

  39. December 12, 2010  5:46 pm by Linux noob Reply

    hi i tried it but it did not work and it says root@me~#

  40. January 27, 2011  8:53 pm by Alex Reply

    Check my tool for the brightness adjustment.

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  42. May 7, 2011  7:28 am by Ricky Reply

    wow, thank you very much. I'm really a new guy of Linux.

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    I was just searching for this info for a while. After six hours of continuous Googleing, at last I got it in your web site. I wonder what is the lack of Google strategy that do not rank this kind of informative sites in top of the list. Generally the top sites are full of garbage.

  44. January 26, 2012  4:19 pm by ppm Reply

    It worked for my HP Pavilion tx 1000 / 1215 laptop.Thanks buddy.

  45. Pingback : How to change brightness on linux desktop through the command line? | | Atutz , Linux Server tutorialsAtutz , Linux Server tutorials

  46. September 5, 2012  5:23 am by Chris Reply

    Thanks! This is handy at night during late night coding sessions

  47. March 29, 2013  10:03 pm by florida cpa Reply

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    I do not know who you are but certainly you're going to a famous blogger if you are not already ;) Cheers!

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