canonical [--comments|:c] [--filter|:f xpath] [expression]
This commands prints a canonical XML representing nodes specified by its argument (or current node, if no argument is given).
--comments or
:c removes comments
from the resulting XML.
--filter or :f
can be used to filter
the resulting XML so that it only contains
nodes explicitly included in the given node-set.
For details see "Canonical XML" or "Exclusive XML Canonicalization" W3C recommendations.