$$ echo THIS IS THE SAME AS xml_split -v Herkum.xml
$$ xml_split -v -c "level(1)" Herkum.xml
generating main file Herkum-00.xml
generating Herkum-01.xml
generating Herkum-02.xml
$$ cat Herkum-00.xml && echo
<root>
<?merge  subdocs = 0 :Herkum-01.xml?>
<?merge  subdocs = 0 :Herkum-02.xml?>
</root>
$$ cat Herkum-01.xml && echo
<a>
  <b>Test</b>
</a>
$$ cat Herkum-02.xml && echo
<aa>
  <b>Test</b>
</aa>