CPU load watcher: sends email when the load average changes by at least one full point

loadwatch.php

<?php

// Install me via cron:
// [email protected]
// * * * * * /usr/local/bin/php /home/someaccount/loadwatch.php

$fields = explode(' ', file_get_contents('/proc/loadavg'));
$avg = $fields[0];

$last = @file_get_contents("/home/gps/cpulast.txt");
if (!strlen($last))
{
  $last = -1;
}

if (abs(floor($last) - floor($avg)) >= 1.0)
{
  echo("CPU load is now $avg");
  file_put_contents("/home/gps/cpulast.txt", $avg);
}

$out = fopen("/home/gps/cpu.csv", "a");
fwrite($out, date('Y-m-d H:i:s') . ',' . $avg . "\n");
fclose($out);