Notebook Ubuntu Brightness control command line

After installing the Ubuntu dual system, the notebook originally adjusts the brightness of the screen shortcut keys can not be used (will show the brightness bar but the actual brightness does not change).

Dragging the brightness bar from the system settings has no effect.

Try to solve the problem with the command line.

1-Query the maximum brightness with the command line (my Notebook Flat panel monitor is 9)

Cat/sys/class/backlight/acpi_video0/max_brightness

2-Open/etc/rc.local

sudo gedit/etc/rc.local

3-Add a line of text before "Exit 0"

Note: 4 represents the brightness value, you can adjust to the appropriate value, remember to be less than the first step to find the maximum value.

Note: My 9 is the darkest and 1 is the brightest. Different notebooks may not be the same, please try them. Of course, we have to reboot every time.

4-Save, launch.

When you restart your computer, the screen brightness is the value you set.

Above. From Wikipedia textbook

MD--Bad to make ...