What are the best practices for setting file permissions in PHP when working on an online server?

When working on an online server in PHP, it is important to set file permissions correctly to ensure security and prevent unauthorized access to sensitive files. A common best practice is to set directories to 755 and files to 644, which allows read and execute permissions for directories and read-only permissions for files.

// Set directory permissions to 755
chmod("/path/to/directory", 0755);

// Set file permissions to 644
chmod("/path/to/file", 0644);