Command-line detection of anomalies

Hi:

I'd like to be able to detect anomalies via the command-line.  I have
begun to explore Holt-Winters, PREDICT, etc.  They can all display
anomalies in a graph.  But I think Holt-Winters is the only one that
will let me get at the data on the command-line via rrdfetch.  Is that
true?

Maybe this question is essentially the same as my previous question
about getting graph data without the graph [1] :)  In that thread Dan
Cech mentions using rrdgraph in "report" mode.  But IIUC you can't
report a series of numbers, just a single number.  That is, you can't
print the result of a DEF or a CDEF.

Am I missing anything?  Are there any plans to make it easier to get at
raw data?  I think the prediction and anomaly-detection features would
get used more if they could be scripted.  As is, I can't possibly look
all of the graphs once a day (or week or month :) to find anomalies.

And, of course, thanks for rrdtool--it's awesome!

Footnotes: 
[1]  http://thread.gmane.org/gmane.comp.db.rrdtool.devel/3427/