Select Code to Download

  <record>
    <title>Learning Perl</title>
    <category>Programming</category>
  </record>

  <record>
    <title>Learning Perl</title>
    <category>Programming,Learning,Perl</category>
  </record>

use warnings;
use strict;
...
    <url>http://www.oreilly.com/catalog/lpython2/index.html</url>
  </record>
</records>

$ perl modify_category.pl
<?xml version='1.0'?>
...
    <category>Programming,Learning,Python</category>
    <title>Learning Python</title></record>
</records>