Thijs Feryn gave a presentation on the CLI (command line interface) SAPI for PHP. The CLI SAPI allows PHP scripts to be run from the command line/terminal instead of through a web server. Some key points of the CLI SAPI include reading arguments from $argv, reading input from STDIN, writing output to STDOUT, and having full control over script execution without timeouts. The CLI SAPI is useful for tasks like cronjobs, batch processing, and applications without a web frontend.