PHP Simple Stats, CPU, Memory, Disc and Load Usage

gistfile1.php

<?php
$load=sys_getloadavg();
$results=array(
	'memory' => round(exec("printf \$(free -m| grep  Mem | awk '{ print \$3/\$2*100 }')"),2),
	'disc'   => (100-round(disk_free_space(getcwd())/disk_total_space (getcwd()) * 100,2)),
	'cpu'    => round(exec("grep 'cpu ' /proc/stat | awk '{cpu_usage=($2+$4)*100/($2+$4+$5)} END {print cpu_usage}'"),2),
	'load'   => $load[0]
);

die(json_encode($results));