#!/usr/bin/perl -w

use strict;
use XML::LibXML;

my $parser = XML::LibXML->new();
my $doc = $parser->parse_string(join "", <DATA>);

# copy the node, then delete it
my $from_path = q{/category/subcategory/product[product_id = "800.55.01"]};
my @from_nodes = $doc->findnodes( $from_path);
my $dead = $from_nodes[0];  # Assume there can be only one
$dead->unbindNode;

# paste the node to a new location
my $to_path = q{/category/subcategory[@name = "Grand Arabica"]};
my @to_nodes = $doc->findnodes( $to_path);
my $paste = $to_nodes[0];  # Assume there can be only one
my $lastnode = $paste->lastChild();
$paste->insertAfter( $dead, $lastnode);

print $doc->toString([0]);