#!/usr/bin/perl

# define script defaults (change these to suit your needs or supply them in your script calls)
my %defaults = 	(	foo			=>		"bar",
						bar			=>	"foo",
						...			=>	...,
);

# to handle parameter passing
use CGI;

# get the script parameters; 1st from the ARGV array (in the case of SSI calls) then the QUERY_STRING
if (@ARGV) { $input = new CGI ( join "&" => @ARGV ); } else { $input = new CGI; }

# set the values for parameters omitted by user to the %defaults values
for ( keys %defaults ) { $input->param(-name=>$_,-value=>$defaults{$_}) unless $input->param($_); }

#########
# the rest of your program here
#########