lightctl - control USB power on/off on BeagleBone Black

lightctl

#!/usr/bin/bash
function lighton {
	until sudo devmem2 0x47401c60 b 0x01
	do
		echo "Trying again"
	done
}

function lightoff {
	until sudo devmem2 0x47401c60 b 0x00
	do
		echo "Trying again"
	done
}

function printhelp {
	echo 'Usage: lightctl (on|off|status)'
	echo 'Need passwordless sudo.'
}

function getstatus {
	until sudo devmem2 0x47401c60 b
	do
		echo "Trying again"
	done
}

function parsestatus {
	outpu=$(getstatus)
	if [[ $outpu == *'0x128'* ]];
	then
		echo 'off'
	elif [[ $outpu == *'0x25'* ]];
	then
		echo 'on'
	else
		echo "error"
	fi
}

if [ $# -eq 0 ];
then
	printhelp
elif [ $# -eq 1 ];
then
	if [ "$1" == 'on' ];
	then
		lighton &> /dev/null
	elif [ "$1" == 'off' ];
	then
		lightoff &> /dev/null
	elif [ "$1" == 'status' ];
	then
		parsestatus
	else
		printhelp
	fi
else
	printhelp
fi

Need devmem2 and passwordless sudo.