There is a misconception about CGI. You should use environment variables to pass arguments to programs rather than using command line options. Because, CGI uses command line for other purposes.  Instead, the following two main environment variables should be used: 

QUERY_STRING 
Defined as anything which follows the first ? (question mark) in the URL. This information could be added either by an ISINDEX document or by an HTML form (with the GET action). 
This string is encoded in the standard URL format of changing spaces to + and encoding special characters with %xx hexadecimal encoding. In order to use these arguments, we should perform a decoding operation. 

PATH_INFO 
CGI allows for extra information to be embedded in the URL for your gateway which can be used to transmit extra context-specific information to the scripts. The mose useful example of PATH_INFO is transmitting file locations to the CGI program.