CGI (Common Gateway Interface) is a standard for running external programs from a Web server. CGI allows the returned HTML page to be dynamic - for example, with a CGI script you could access information in a database and format the results as part of an HTML page. Not surprisingly, CGI scripts are very popular and used extensively throughout the World Wide Web.

There are a number of very good introduction to CGI documents available on the Web. The information given below is a summary of the most important points to remember when using CGI. Please refer to the following for a more in-depth introduction:

• Intro to PHP - one of the best introductions available.

• Ada's Introduction to CGI - a useful introduction.

Key points to bear in mind when using CGI scripts:

• The pre installed scripts available through cPanel are the easiest to use, but if a certain script does not do exactly what you want, feel free to look for better scripts on the Web. You can usually find a script to do almost anything, especially if you are prepared to pay.

• Read all available documentation on a particular script before using it. This will help avoid most problems.

• CHMOD ("Change Mode") means change the permissions on a particular file (usually the script itself). The cPanel File Manager allows you to quickly do this, as do most FTP tools.

• Important - after uploading cgi-bin scripts, CHMOD to 755 (unless the script documentation specifically states otherwise). For example, you need to CHMOD the pre-installed cPanel scripts to 755 to use them properly.

• Many scripts need to know the path to Perl (scripting language engine) and to sendmail (HTTP mail engine). You can find this information on the front page of cPanel.

• Make sure you test your scripts repeatedly! Testing is vital to make sure everything is working to your satisfaction.