TIL that you can have query strings without query strings. Man, I wish I knew this a decade ago.

test.cgi

#!/usr/bin/perl
use strict ;
use warnings ;
use 5.010 ;
use CGI ;
use CGI::Carp qw( fatalsToBrowser ) ;
use Data::Dumper ;

use lib '/home/ltl/lib' ;
use LTLcommon qw{ pi_Readfile } ;

$LTLcommon::UseTestFiles = 0 ;
my $q = new CGI ;

print $q->header() ;
print $q->start_html(
    -style => '/~jacoby/env.css',
    -title => 'TEST',
    -head  => $q->Link( {
            -rel  => 'icon',
            -type => 'image/vnd.microsoft.icon',
            -href => '/~maize/Images/favicon.ico',
            }
        ),
        ) ;
print main( $q ) ;
print $q->end_html() ;

#---------- ---------- ---------- ---------- ---------- ---------- ----------
sub main {
    my ( $q )       = @_ ;
    my $pi_readfile = pi_Readfile() ;
    my @pi_list     = sort keys %$pi_readfile ;
    my $param ;
    %$param = map { $_ => $q->param( $_ ) } $q->param() ;
    my @path = grep { /\w/ } split( /\//, $q->path_info ) ;
    my $path = $path[0] ;
    my $url = $q->url() ;

    my $output ;
    $output .= $q->div( $url ) ;
    $output .= $q->div( $path ) ;

    if ( $path && $pi_readfile->{ $path } ) {
        my $pi = $pi_readfile->{ $path } ;
        $output .= $q->pre( Dumper $pi ) ;
        }
    else {
        for my $pi ( @pi_list ) {
            my $link = join '/', $url, $pi ;
            $output .= $q->p( $q->a( { href => $link }, $pi ) );
            }
        }

    return $q->div( $output ) ;
    }

#---------- ---------- ---------- ---------- ---------- ---------- ----------