Ubuntu保存屏幕亮度

参考了这篇文章： http://www.aichengxu.com/article/系统优化/25720_12.html

文章里是直接把亮度设成了 5， 我这里稍微改了一下，可以记录之前调节的亮度。具体做法：

sudo vim /etc/rc.local

原内容如下：

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

exit 0

在 exit 0 之前添加两行代码，如下：

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

bri=cat /sys/class/backlight/acpi_video0/actual_brightness
echo $bri > /sys/class/backlight/acpi_video0/brightness

exit 0

就是把原本的实际亮度写到启动时候加载的那个亮度里，不同电脑具体路径可能有所不同。

---

更新：不知道为什么上面的方法失效了，最终还是改用直接写入最低亮度的方法：
echo 0 > /sys/class/backlight/acpi_video0/brightness