These are aliases that I use on my linux installation on a ASUS-laptop with backlight on keyboard:

#ROOTS Aliases
#Set keyboard backlights from 0 (dark) to 3
alias fnb0='echo 0 > /sys/class/leds/asus::kbd_backlight/brightness'
alias fnb1='echo 1 > /sys/class/leds/asus::kbd_backlight/brightness'
alias fnb2='echo 2 > /sys/class/leds/asus::kbd_backlight/brightness'
alias fnb3='echo 3 > /sys/class/leds/asus::kbd_backlight/brightness'