ref: 88ccea37f65b87312292b2b1a107c39927c6a2c3
dir: /sys/src/cmd/bitsy/light.rc/
#!/bin/rc #master file is /sys/src/cmd/bitsy/light.rc switch($1){ case on echo -n 2 1 0x80 > /dev/backlight case off echo -n 2 0 0x80 > /dev/backlight case auto echo -n 1 1 0x80 > /dev/backlight case * echo -n 2 1 $1 > /dev/backlight }