----- Original Message -----
 Hello Dave,
 
 The attachment is the code that adds two command, rbtree and rdtree.  The
 commands work well, but, onsidering some code is a copy of command list,
 I think the code still need a big change.
  
Hi Qiao,
I haven't been able to spend much time looking at this patch, but
these are my initial impressions.
My suggestion of a single "tree" command was just that, where there 
would be a single "tree" command, and that command would require an
option to make the differentiation between an red-black tree and a 
radix tree. 
I don't quite understand why you *only* have the "[-o] offset" advertised 
for the rbtree command?  Virtually every instance of a radix_tree_root
structure in the kernel is embedded in a data structure, similar to the 
typical usage of an rb_root.  Why the difference? 
The "-H start" option should probably be something like "-R" for
"root".
When -H is used in the list command, it refers to list_[H]ead.
The examples in the help pages are not particularly helpful.
I don't know what "tts.rb" refers to?  Can you find better examples
that the user can relate to? 
Also, a clear explanation of what the "position information" actually
means would be helpful.
Thanks,
  Dave