PHP operating the file

You can easily operate the files with php. However, you should notice an important point. The privilege of the folders contain the file should be open to you!
$fh = fopen('test/test.file','wb');
if(is_writable('test/test.file') == false)
print "this file can't be writen!";
if (! $fh) {
print "Error opening test.file ";
}else{
fwrite($fh, "test the file operation with php\n");
}
fclose($fh);