[TriLUG] CLI XML diff (and patch?) tools?

[Andy Random]

Hi,

Does anybody know of/have a recommendation for a command line based XML 
diff tool?

If possible I'd like an XML patch tool as well, but that is less 
important.

Preferably something written in Perl/Python/Ruby etc. (or that comes with 
suitable RHEL 5.x RPMs:)

I can find several with a web search but they all seem to be defunct (last 
update 2003 etc.) and I'd really like something that is maintained.

Any suggestion?

Thanks,

   Andy