CGI is short for " The Common Gateway Interface ". CGI is a method used to exchange data between the server (hosts your web site) and a web client (your browser).

Some of the more common uses of CGI include:

• Guestbooks
• Email Forms
• Mailing List Maintenance

CGI scripts are simply text or ASCII files which are 'compiled on the fly' (interpreted by a program on the server rather than the browser) by the Perl interpreter. They can be edited or created on any text editor and must be saved with a '.cgi' file extension. The common choice for writing and processing CGI is Perl, or "Practical extraction and reporting language". A CGI program can however be compiled 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.

In order to use CGI, you must be able to do a few things with your Internet account. You must be able to:

• Telnet into the system
  
• Create directories
  
• Change directory modifications

• Your web address must have a directory named '/cgi-bin/' to include your cgi scripts in.
• When uploading by ftp it needs to be uploaded in 'Text' or 'ASCII' mode and not in 'Automatic' or 'Binary' mode.
• With ftp you may want to set permissions by using chmod so that users cannot alter, use or view your script.

CGI FAQ

• Where to put cgi scripts - CGI-BIN
• Uploading CGI Scripts
• Setting permissions to your cgi script
  

CGI Perl FAQ

• Basics
• How to start a cgi script with Perl interpreter
• How to make your Perl CGI script more efficient