Understanding PHP CLI
Working with the console in PHP is quite easy via the help of PHP CLI SAPI, or just PHP CLI for short. PHP CLI was first introduced in PHP 4.2.0 as an experimental feature, and, soon after, it became fully supported and enabled by default in the later versions of PHP. The great thing about it is that it is available on all popular operating systems (Linux, Windows, OSX, Solaris). This makes it easy to write console applications that execute pretty much on any platform.
Note
Check out https://en.wikipedia.org/wiki/Command-line_interface and https://en.wikipedia.org/wiki/Server_Application_Programming_Interface for more elaborate descriptions of general CLI and SAPI abbreviations.
PHP CLI is not the only SAPI interface supported by PHP. Using the php_sapi_name() function, we can get a name of the current interface that PHP is using. Other possible interfaces include aolserver, apache, apache2handler, cgi, cgi-fcgi, cli, cli-server, continuity, embed, fpm-fcgi, and others...
