Dynamic Content with CGI . Configuring Apache to permit CGI . ... Writing a CGI program . ... File permissions . ... The CGI (Common Gateway Interface) defines a way for a web server to interact with external content-generating programs, which are often referred to as CGI programs or CGI scripts. ... So, the example above tells Apache that any request for a resource beginning with /cgi-bin/ should be served from the directory /usr/local/apache/cgi-bin/ , and should be treated as a CGI program. ...