• The following commands with an asterisk expect only one backlight controller at /sys/class/backlight
• This was only tested on one laptop with intel_backlight
• See Power Management notes on how to add backlight changes to a udev script
• See backlight for more details

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ls '/sys/class/backlight'

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cat '/sys/class/backlight/'*'/brightness'

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cat '/sys/class/backlight/'*'/max_brightness'

• Change 376 to desired brightness
• Desired brightness must be under max_brightness value

echo "376" | sudo tee '/sys/class/backlight/'*'/brightness' > '/dev/null'

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echo "$(cat '/sys/class/backlight/'*'/max_brightness')" | sudo tee '/sys/class/backlight/'*'/brightness' > '/dev/null'