PHP从子目录中删除文件？

Question

I have a PHP script that deletes files. It can delete files from my root directory, but when I try to delete from a subdirectory, it says "Permission denied". I know the file exists and PHP can access it because I can read and write to the file, but I can't delete it. Why?

EDIT: If this is relevant, I am using Zymic hosting. But I have another site on Zymic where the deleting works fine. I don't get it...

EDIT: I use ajax to access the PHP file with the code to delete, and the ajax sends the file name to delete. I know the file name it sends is correct, because the warning message prints it for me. The PHP code is simply:

$file=$_POST['file'];
echo unlink($file);

EDIT: I fixed it! I don't know why this worked, but I FTP-chmodded the directory from 755 to 775 Can anyone tell me why it worked?

Answer 1

To delete the file you need write permissions to the folder that contains it, check that first.

CHMOD xxx -> Owner Group Other

first case: 755 - Owner (read, write, execute), Group (read, execute), Other (read, execute)

second case: 775 - Owner (read, write, execute), Group (read, write, execute), Other (read, execute)