Permission denied on sysfs files

I'm messing around with my raspberry pi, and currently I'm trying to change the color of one of the LEDs on the board executing a shell script and its arguments: pi@raspberrypi:~/morpheus/scripts $ bash ./set-rgb-led.sh level 50 50 50 When inputting above command, I receive following: ./set-rgb-led.sh: line 19: /sys/class/leds/morpheus:level:red/brightness: Permission denied ./set-rgb-led.sh: line 19: /sys/class/leds/morpheus:level:green/brightness: Permission denied ./set-rgb-led.sh: line 19: /sys/class/leds/morpheus:level:blue/brightness: Permission denied To check up on permissions I ran getfacl set-rgb-led.sh, which tells me following information: # file: set-rgb-led.sh # owner: pi # group: pi user::rwx group::--x other::--x I've tryed using the chmod +x command and alike permission changing commands, but I can't seem to gain proper access. What am I missing so I can gain control of the file?