<?php
$start = time(NULL);
error_reporting(~E_ALL);

$file = file_get_contents("blabla.txt");
$pieces = explode("\n", trim($file));

foreach($pieces as $piece)
{
	if(strcmp($piece, "textthatexistsinthefile") == 0)
	{
	     echo 'yes';
	}

}

$end = time(NULL);

echo 'time '.$end - $start;

?>