Are there any best practices for handling file and directory creation and deletion in PHP scripts to avoid permission denied errors when using FTP programs?

When creating or deleting files and directories in PHP scripts that will be accessed via FTP programs, it is important to ensure that the correct permissions are set. One way to avoid permission denied errors is to explicitly set the permissions using the `chmod()` function after creating the file or directory.

// Create a directory and set permissions
$dir = 'new_directory';
mkdir($dir);
chmod($dir, 0777);

// Create a file and set permissions
$file = 'new_file.txt';
$handle = fopen($file, 'w');
fclose($handle);
chmod($file, 0666);

// Delete a file
$file_to_delete = 'file_to_delete.txt';
unlink($file_to_delete);

// Delete a directory
$dir_to_delete = 'directory_to_delete';
rmdir($dir_to_delete);