This worked for me. 
<html>
<head>
<title>ssi demo</title>
</head>
<body>
<h1>ssi demo</h1>
<!--#include virtual="ssi_test.cgi?q=hi!"-->
</body>
</html>

[download]
ssi_test.cgi 
#!/usr/bin/perl

use strict;
use warnings;
use CGI::Simple;

my $q = CGI::Simple->new;
print $q->header;
my $param = $q->param('q');
print qq|<h1>$param</h1>|;

[download]
output 
ssi demo
hi!

[download]

In reply to Re: Passing data via URL in include by wfsp
in thread Passing data via URL in include by i_am_jeers_colon

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