Ubuntu Brightness By Command Line

From:

user@laptop:~$ ls /sys/class/backlight/
acpi_video0
user@laptop:~$ cat /sys/class/backlight/*/brightness 
1
user@laptop:~$ cat /sys/class/backlight/*/max_brightness 
7
user@laptop:~$ sudo su -c "echo 7 > /sys/class/backlight/*/brightness"
user@laptop:~$ cat /sys/class/backlight/*/brightness 
7