You can put your script at a web address where only you will find it and then tell the debugger to start and contact you at your terminal so you can debug the script in its full environment. The devil is in the details, but there are a lot of options on how to do this.

Something like:

BEGIN {
    if(  @ARGV  &&  "-d" eq $ARGV[0]  ) {
        shift @ARGV;
    } else {
        my $tty= ( split ' ', (grep /^tye\b/, `who`)[0] )[1];
        $ENV{PERL_DBOPTS}= "TTY=$tty";
        exec $^X, "-d", $0, "-d", @ARGV;
    }
}
[download]

might work (you'll have to give the CGI user permission to read and write from/to your tty).

        - tye (but my friends call me "Tye")