Common Gateway Interface (CGI)

CGI stands for Common Gateway Interface. It is a protocol, whose specification enables web server to execute programs. CGI is platform independent, and can be used with any programming language.

PHP may be build as a CGI, but also as a webserver module or a CGI server.

CGI was widely used in the early days of the web, more modern web development approaches, such as server-side scripting have largely replaced CGI in contemporary web development due to performance and security considerations.

Documentation

Related : FastCGI Process Manager (FPM), FastCGI, Command Line Interface (CLI), FastCGI Process Manager (FPM), Server Application Programming Interface (SAPI)

Added in PHP CGI and command line setups