تابع ‎fread()‎‎ در PHP

<?php
$file = fopen("test.txt","r");
fread($file,"10");
fclose($file);
?>
<?php
$file = fopen("test.txt","r");
fread($file,"10");
fclose($file);
?>اجرای کد

<?php
$file = fopen("test.txt","r");
fread($file,filesize("test.txt"));
fclose($file);
?>
<?php
$file = fopen("test.txt","r");
fread($file,filesize("test.txt"));
fclose($file);
?>اجرای کد