A slightly better version of the script that accepts 'on' and 'off' arguments. If no argument is given it toggles the backlight state
#!/bin/bash
filename='/sys/class/backlight/fb_ili9340/bl_power'
read -r state<$filename
if [ "$1" = "off" ]; then
echo 1 > /sys/class/backlight/fb_ili9340/bl_power
elif [ "$1" = "on" ]; then
echo 0 > /sys/class/backlight/fb_ili9340/bl_power
else
echo "This command accepts the following arguments"
echo "on - turns the backlight on"
echo "off - turns the backlight off"
echo "If no argument is given the backlight will toggle"
echo "No state selcted, toggling."
if [ "$state" = "0" ]; then
echo 1 > /sys/class/backlight/fb_ili9340/bl_power
else
echo 0 > /sys/class/backlight/fb_ili9340/bl_power
fi
fi