The default is to build PHP as a CGI program. This creates a command line interpreter, which can be used for CGI processing, or for non-web-related PHP scripting. If you are running a web server PHP has module support for, you should generally go for that solution for performance reasons. However, the CGI version enables users to run different PHP-enabled pages under different user-ids.
A server deployed in CGI mode is open to several possible vulnerabilities. Please read our CGI security section to learn how to defend yourself from such attacks.
As of PHP 4.3.0, some important additions have happened to PHP. A new SAPI named CLI also exists and it has the same name as the CGI binary. What is installed at {PREFIX}/bin/php depends on your configure line and this is described in detail in the manual section named Using PHP from the command line. For further details please read that section of the manual.
If you have built PHP as a CGI program, you may test your build by typing make test. It is always a good idea to test your build. This way you may catch a problem with PHP on your platform early instead of having to struggle with it later.
Some server supplied environment variables are not defined in the current » CGI/1.1 specification. Only the following variables are defined there: AUTH_TYPE, CONTENT_LENGTH, CONTENT_TYPE, GATEWAY_INTERFACE, PATH_INFO, PATH_TRANSLATED, QUERY_STRING, REMOTE_ADDR, REMOTE_HOST, REMOTE_IDENT, REMOTE_USER, REQUEST_METHOD, SCRIPT_NAME, SERVER_NAME, SERVER_PORT, SERVER_PROTOCOL, and SERVER_SOFTWARE. Everything else should be treated as 'vendor extensions'.