<?php
$fp = fopen("test.txt", "r");
$tekst = fread($fp, 100);
echo $tekst;
echo filesize ("test.txt")."<br>";
fclose ($fp);
$fp = fopen("test.txt", "w");
flock($fp, LOCK_EX);
if (!flock($fp, LOCK_EX)) {
	fclose ($fp);
}
else {
	echo "Plik jest zablokowany </br>";

$dane = "aaaaaa";
fputs ($fp, $dane);
flock ($fp, LOCK_UN);
echo fread ($fp, filesize ("test.txt"));
fclose ($fp);
}
?>