通过命令设置笔记本kali_linux的屏幕亮度

参考资料: 

1. 调整屏幕亮度第一种方法：xrandr ,优点是简单方便
缺点是:However, this is a software only modification, if your hardware has support to actually change the brightness, you will probably prefer to use xbacklight.

#xrandr | grep connected | cut -f1 -d" "
Use the output name found (in this case "eDP-1") and adjust the brightness
#xrandr --output eDP-1 --brightness 0.7

2. 调整屏幕亮度第二种方法：xbacklight，始终无法使用xbacklight -set 命令，不论怎么在/etc/X11/xorg.conf里面尝试各种内容，结果都是失败，最后放弃了用命令，而是改成了直接echo 6|tee 这种方式.

#安装
apt-get install xbacklight

root@kali:~# xbacklight -set 7
No outputs have backlight property

root@kali:~# readlink /sys/class/backlight/acpi_video0
../../devices/pci0000:00/0000:00:02.0/backlight/acpi_video0

root@kali:~# find /sys/ -type f -iname '*brightness*'
/sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0/leds/phy0-led/max_brightness
/sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0/leds/phy0-led/brightness
/sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/max_brightness
/sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/brightness
/sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/actual_brightness
/sys/devices/platform/i8042/serio0/input/input0/input0::capslock/max_brightness
/sys/devices/platform/i8042/serio0/input/input0/input0::capslock/brightness
/sys/devices/platform/i8042/serio0/input/input0/input0::scrolllock/max_brightness
/sys/devices/platform/i8042/serio0/input/input0/input0::scrolllock/brightness
/sys/devices/platform/i8042/serio0/input/input0/input0::numlock/max_brightness
/sys/devices/platform/i8042/serio0/input/input0/input0::numlock/brightness
/sys/module/video/parameters/brightness_switch_enabled
/sys/module/i915/parameters/invert_brightness

#最大亮度只有９，多数笔记本最大亮度应该是１５
root@kali:~# cat /sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/max_brightness
9

#当前亮度５
cat /sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/actual_brightness
5

＃设置新的亮度
echo 7 |tee /sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/brightness