XSH: XML Editing Shell

Just fixed a small xsh
script that I wrote months ago in my spare time to walk a
Torrus configuration snapshot.

A coworker asked me If I had a way to easily provide an overview/outline
of the data that was being collected via Torrus for a customer.
Fortunately the answer was yes, and it didn't involve the complex, ugly
and not quite functional grep and awk statements I used the first time I
tried to get quick overview of the XML tree.

The problem was that in order to get the comment I was stepping into the
comment parameter to get the value when I should have been doing

$comment = string(param[attribute::name='comment']/attribute::value);        

Then I wasn't stepping back out, prematurely ending the loop and missing
additional trees and leaves.

The Final output looks a bit like this, but goes on to enumerate all of
the data that is collected and displayed.

  Subtree = Devices ''
      Subtree = router-name '2651XM chassis, Hw Serial#: XXXXXXXXX (XXXXXXXX), Hw Revision: 0x301'
          Subtree = Buffer_Usage 'Buffer usage statistics'
              Subtree = Small_Buffers 'Buffer usage statistics'
                  Leaf = Free   'Number of Free Small Buffers'
                  Leaf = Max    'Max Small Buffers'
                  Leaf = Hits   'Small Buffer Hits'
                  Leaf = Misses 'Small Buffer Misses'
                  Leaf = Creates        'Small Buffer Creates'
                  Leaf = Trims  'Small Buffer Trims'        

The snapshot XML in part looks like