<?php

$myFile = file_get_contents("./file.txt");
$myTempFile = "./temp.txt";
$fh = fopen($myTempFile,'r');
$key = (fgets($fh));//Save first line content




            echo "$myFilen"; // this returns "Stuff abab"
            echo "$keyn"; //this returns "abab"
           if(strpos($myFile, $key)!== FALSE) //This does not work
            {

             //stuff

            }

}
?>