// Load Kohana log package Kohana::load('log'); // Create a new file logger $config = array('directory' => 'logs'); $log = Log::instance('file', $config); // Log a message $log->add(Log::DEBUG, 'Hello, Kohana log!');In this example, we first load the Kohana log package using the `Kohana::load()` method. Then, we create a new file logger by instantiating the `Log` class with the `'file'` driver and a configuration array that specifies the directory where the log files should be stored. Finally, we log a message using the `add()` method of the logger, which takes two arguments: the log level of the message (here, `Log::DEBUG`) and the message itself. Other examples of using the Kohana log include: - Access log: logging incoming requests and outgoing responses to a file or database for analysis and optimization purposes - Error log: logging PHP errors, warnings and notices to a separate log file or database table for easier debugging and troubleshooting - Performance log: logging execution time and memory usage of critical code paths or functions for profiling and optimization In summary, the Kohana log is a flexible and versatile logging library that can help developers monitor and improve their PHP applications.