gistfile1.php

<?php

function LineIterator($file) {
    $handle = fopen($file, 'r');
    return function() use($handle) {
        if(!feof($handle)) {
            return fgets($handle);
        }
        fclose($handle);
    };
}

$iterator = LineIterator('/etc/hosts');
while($line = $iterator()) {
    echo $line;
}