You could try xmllint
The xmllint program parses one or more
XML files, specified on the command
line as xmlfile. It prints various
types of output, depending upon the
options selected. It is useful for
detecting errors both in XML code and
in the XML parser itse
It allows you select elements in the XML doc by xpath, using the –pattern option.
On Mac OS X (Yosemite), it is installed by default.
On Ubuntu, if it is not already installed, you can run apt-get install libxml2-utils