How can I turn off the LEDs on the front of my laptop(ASUS K501LX-NH52)?

On Linux check this directory.

/sys/class/leds/

If there are subdirectories, look inside for a file called trigger Reading the trigger file will list the available LED control parameters, with the current one surrounded by brackets.

To change the trigger parameter, just write the name of the parameter to the trigger file.

Another file, brightness can be used to disable to LED as well. Writing 0 to brightness will shut off the LED that that particular subdirectory controls.

To disable all controllable LEDs as a test, you can try this command:

sudo echo -n 0 > /sys/class/leds/*/brightness

If you caot control the LEDs this way, unplugging the board may be the only way.