What are best practices for securely managing file permissions in PHP applications?

When managing file permissions in PHP applications, it is important to follow best practices to ensure security. This includes setting appropriate permissions for files and directories to prevent unauthorized access or modifications. One common approach is to use the chmod function to set specific permissions on files and directories.

// Set file permissions to restrict access
$file = 'example.txt';
$permissions = 0644; // Read and write permissions for owner, read-only for others
if (file_exists($file)) {
    chmod($file, $permissions);
    echo "File permissions set successfully.";
} else {
    echo "File does not exist.";
}