How can output buffering and data flushing be optimized in PHP scripts to ensure timely and accurate data transmission between scripts and external processes like shell scripts?

To optimize output buffering and data flushing in PHP scripts for timely and accurate data transmission, you can use the `ob_flush()` function to flush the output buffer and send the data to the client immediately. This ensures that the data is transmitted in a timely manner without waiting for the script to finish execution.

// Enable output buffering
ob_start();

// Your PHP script code here

// Flush the output buffer
ob_flush();