(BeagleBoneBlack)ubuntu@localhost:~$ cat /sys/class/leds/beaglebone\:green\:heartbeat/triger
[none] kbd-scrollock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock nand-disk usb-gadget usb-host mmc0 mmc1 cpu0