设置HP DV6笔记本显示屏亮度

笔记本的亮度在Ubuntu里面不可以调整，Google了一下，找到了办法(原文)，具体是写了一个script来调整

亮度1-10代表10%到100%

   1: clear

   2: echo "Enter a brightness value (1-10)"

   3: read brightness

   4: sudo sh -c 'echo $brightness > /sys/devices/virtual/backlight/acpi_video0/brightness'

   5: echo "Brightness set to $brightness."