Shell to run something when CPU IDLE > 99

idle.sh

#!/usr/bin/env bash

# check systems idle time, run commands depending on that

function get_idle { 
	idle=$(top -bn2 | grep "Cpu(s)"|tail -n 1|sed "s/.*, *\([0-9.]*\)%* id.*/\1/")
	echo "$idle"
}

function main_loop {
	while true; do
		idle="$(get_idle)"
		if [[ $idle > 99 ]]
		then
		    echo "Do stuff now: $idle"
		else
		    echo "Stop doing stuff now: $idle"
		fi
		sleep 30
	done
}

main_loop