what is cgi?

The Common Gateway Interface (CGI) is a standard protocol which interfaces the interaction between programming applications and information servers. This allows the server to pass requests from a client web browser to the external application. The web server can then return the output from the application to the web browser.
A plain HTML document that the Web daemon retrieves is static, which means it exists in a constant state: a text file that doesn't change. A CGI program, on the other hand, is executed in real-time, so that it can output dynamic information .

An example of a CGI program is the one implementing a wiki (a type of website that allows users to easily add, remove, or otherwise edit and change some available content, sometimes without the need for registration): the user agent requests the name of an entry; the server will retrieve the source of that entry's page (if one exists), transform it into HTML, and send the result back to the browser or prompt the user to create it. All wiki operations are managed by this one program.

CGI programing can be written in any language that allows it to be executed on the system, such as:

• C/C++
• Fortran
• PERL
• TCL
• Any Unix shell
• Visual Basic
• AppleScript

• W3
• CGI