Yes, you can run your script from the command line to see what output it produces, including the HTTP headers which the browser doesn't show you. Something like: `perl -wT foo.cgi`. Use -c to make sure the script compiles, then leave it off to see what output you get.
Because CGI scripts get their input from the environment and standard input, you can run your script from the command line with all the data it would get from the web server. For example, you can set QUERY_STRING in your shell's environment to 'id=7&name=bob'.
The CGI module provides a debug mode when run under the shell to make this easier. Run the script from the shell, and you can include parameters and values on the command line or pass them through standard input. (See the DEBUGGING section of the manpage for more details.)
