新建三个文本文件并给予执行权限：
up.sh
if [ ! -w /sys/class/backlight/intel_backlight/brightness ];then
echo "password" | sudo -S chmod 777 /sys/class/backlight/intel_backlight/brightness
fi
read bright < '/sys/class/backlight/intel_backlight/brightness'
v=600
v=$((4882 / 20 + $bright))
if [ $v -gt 4882 ]; then
v=4882
fi
echo $v | tee /sys/class/backlight/intel_backlight/brightness
down.sh
if [ ! -w /sys/class/backlight/intel_backlight/brightness ];then
echo "password" | sudo -S chmod 777 /sys/class/backlight/intel_backlight/brightness
fi
read bright < '/sys/class/backlight/intel_backlight/brightness'
v=600
v=$(($bright - 4882 / 9 ))
echo $v | tee /sys/class/backlight/intel_backlight/brightness
middle.sh Linux学习，http:// linux.it.net.cn
echo 2441 > /sys/class/backlight/intel_backlight/brightness
使用方法：
提高亮度：
sudo ./up.sh
降低亮度：
sudo ./down.sh
直接调节亮度到50%：
sudo ./middle.sh | 
转播
