There's a great new tutorial on the MGED 'oed' object edit command now available on the BRL-CAD website.  This tutorial was written by Cliff Yapp and provides a good introduction to some of the fundamental command-line object editing capabilities in MGED.  The tutorial gives a brief overview of the command including explanations and examples on how it can be put to use in practice.  The tutorial is available here:
(0.3 MB PDF)

So if you've been having trouble grasping what is meant by left- and right-hand object paths, how to apply matrix transformations on the command line, using keypoints, and what pushed matrices mean, then this document may help you.  Feedback and comments always welcome, and thanks to Cliff for writing the overview!