echo commands for /proc files

[nujinini]

Hi!

Pardon me but I just decided to start another thread in "Misc" to be more specific to what I am trying to achieve. I feel. It is in relations to making the brightness settings of my laptop work using hot keys.

Anyway, as I was trying to search system for possible solutions, I stumbled upon this and have tried to make adjustments to no avail.

root@jun-laptop:/# cd proc

root@jun-laptop:/proc# cd acpi

root@jun-laptop:/proc/acpi# cd video

root@jun-laptop:/proc/acpi/video# cd GFX0

root@jun-laptop:/proc/acpi/video/GFX0# 

root@jun-laptop:/proc/acpi/video/GFX0# cd DD02

root@jun-laptop:/proc/acpi/video/GFX0/DD02# ls
brightness  EDID  info  state

root@jun-laptop:/proc/acpi/video/GFX0/DD02# cat brightness
levels:  5 15 25 35 45 55 65 75 85 95 100
current: 100

A friend who is an avid linux user mentioned that proc files cannot be easily manipulated but he thinks it can be done using "echo"?

If this is truly possible, may I once again request for some help so that I can change the levels of brightness in my system?

As always, thanks in advance!

[Rubberman]

The /proc files are both for current system state information as well as a means to manipulate system settings, such as, in your case, the display brightness. The data you see when you 'cat' one of the files is from the kernel. Try writing the level you want to that same file. Ie: echo 50 >brightness
At worst it will ignore it. At best, your brightness level will change.

[nujinini]

Hello Rubberman!

No dice. Not responding .....

root@jun-laptop:~# cd /proc/acpi/video/GFX0/DD02
root@jun-laptop:/proc/acpi/video/GFX0/DD02# le:echo 50>brightness
le:echo: command not found
root@jun-laptop:/proc/acpi/video/GFX0/DD02# echo 50>brightness

root@jun-laptop:/proc/acpi/video/GFX0/DD02# ls
brightness  EDID  info  state
root@jun-laptop:/proc/acpi/video/GFX0/DD02# cat brightness
levels:  5 15 25 35 45 55 65 75 85 95 100
current: 100
root@jun-laptop:/proc/acpi/video/GFX0/DD02# echo 55>brightness

root@jun-laptop:/proc/acpi/video/GFX0/DD02# ls
brightness  EDID  info  state
root@jun-laptop:/proc/acpi/video/GFX0/DD02# cat brightness
levels:  5 15 25 35 45 55 65 75 85 95 100
current: 100
root@jun-laptop:/proc/acpi/video/GFX0/DD02#

Did I execute it correctly. may I ask?

[Rubberman]

Put a space after the '55' before the '>'. It may not make any difference, but you were telling echo to send a new-line to fd 55, which is probably non-existent, so the results are indeterminate in the way you did it.

[nujinini]

root@jun-laptop:/proc/acpi/video/GFX0/DD02# echo 25 >brightness
root@jun-laptop:/proc/acpi/video/GFX0/DD02# cat brightness
levels:  5 15 25 35 45 55 65 75 85 95 100
current: 25
root@jun-laptop:/proc/acpi/video/GFX0/DD02#

Thank you very much for taking time!

I think I got what I want

[Rubberman]

Kewl! Wonders will never cease! It sounds like you at least have a temporary work-around for this problem.

[nujinini]

Yeah!

I noticed though that even if I set it at 55 or 5, the brightness seems to be the same. Its a little dim though. What was primarily removed was the glare (ouch!!!) off the screen. Kinder to my eyes.

Thanks again.