How to adjust the screen brightness of a notebook in Ubuntu

After Ubuntu is installed, the screen brightness is always very bright, and the method under the window is no longer working. So I searched the internet for a solution as follows, hoping to help beginners who are equally confused.

I: (quick method, temporary) (this method has been tried and is feasible)
1. Press CTRL + ALT + F1 to enter the command line
2. Adjust brightness with shortcut keys
3. Press CTRL + ALT + F7 to return to Gui

Ii. nvclock
Sudo apt-Get install nvclock
Nvclock-S-10

Iii. Xorg. conf
Add option "registrydwords" "enablebrightnesscontrol = 1"

4: (it looks complicated)

After installing the nvidia driver:

1. Switch to an other vt (e.g. CTRL + ALT + F6)

2. Run

Sudo sh-c "echo-n <level>/proc/ACPI/Video/nvid/LCD/brightness"

Where <level> is 0, 10, 25, 40, 55, 70, 85 or 100

------------------------------------------------

NVIDIA driver not installed:
Modify

Sudo gedit/etc/default/ACPI-support

Is:

Enable_laptop_mode = true

Modify

Sudo gedit/etc/laptop-mode/laptop-mode.conf

Is:

Control_brightness = 1

# * If your system has the file "/proc/ACPI/Video/Vid/LCD/brightness" (VID may

# Be vid1 or similar), use this file as brightness_output, and use

# The command "Echo <value>". The possible values can be listed using

# Command:

#

# Cat/proc/ACPI/Video/Vid/LCD/brightness

# * If you have a file/sys/class/backlight/.../brightness, then you can use

# That file as brightness_output, and the command "Echo <value> ".

#

# As far as I understand it the values are between 0 and

# The value contained in the file/sys/class/backlight/.../max_brightness.

From http://www.pczpg.com/a/2010/0528/10048.html

 

We are beginners. Come on!