open(X,">$time.pl") or die "$!";
print X $child; 
close(X);

##</code><code>##

system "perl $time.pl";

##</code><code>##

print "Location: $parent_url?d=1\n\n";

##</code><code>##

unlink "$time.pl";

##</code><code>##

#!perl -w

use strict;
use CGI qw(:standard);

my$url = url(-relative=>1);
my$time=time();
my$d = param('d');
if($d eq '1'){&show;exit}

eval("seek DATA,0,0;"); undef$/; $_=<DATA>; # read self into $_
$_ =~ m/__END__\n(\d.*)/; my$num=$1; $num++; # find target in $_ and change

# build child script with $url and $num (to open, change, save, and run parent) 
my$child = "#!perl -w\n\nuse CGI qw(:standard);\nopen(Z,\"+>>$url\") or die \"\$!\";\nundef\$/;\n\$_=<Z>;\n\$_=~s|__END__\\n(\\d.*)|__END__\\n$num|o;\nseek Z, 0, 0;\ntruncate Z, 0;\nprint Z \$_;\nclose(Z);\nprint \"Location: $url?d=1\\n\\n\";"; 

open(X,">$time.pl") or die "$!"; # create and 
print X $child; close(X); # print and close
system "perl $time.pl"; # and run and
unlink "$time.pl"; # delete child

sub show{
print header,start_html(-title=>'polymorphic perl',-bgcolor=>'#000000');
while(<DATA>){ print qq~<a href="$url"><font size="+5" color="#FFFFFF">$_</font></a>~}}

exit;
__END__
0

##</code><code>##

#!perl -w

use CGI qw(:standard);
open(Z,"+>>pp.pl") or die "$!";
undef$/;
$_=<Z>;
$_=~s|__END__\n(\d.*)|__END__\n8|o;
seek Z, 0, 0;
truncate Z, 0;
print Z $_;
close(Z);
print "Location: pp.pl?d=1\n\n";