"In non technical terms libferris makes the file system and other hierarchical storage systems easier to use. For the geeks out there, libferris is a virtual file system (VFS) that runs in the user address space. (...) Can I mount an XML document as a filesystem?
Yes, you can also modify the XML file, add new attributes, elements, rename parts of the internal structure and have it saved back to disk. You'll also find that many of the command line tools will allow such modifications from scripts already. (...) Can I apply an XSLT to a filesystem? Yes you can. Just mount it as a DOM and apply the stylesheet with xalan-c."
by David Mertz, January 2002. "(...) PYX format is a purely line-oriented format for representing XML documents that allows for much easier processing of XML document contents with common text tools like grep, sed, awk, wc and the usual Unix collection. Libraries in a number of programming languages, as well as command-line tools, exist for converting between XML and PYX formats, and for working with PYX format. This article introduces the PYX format, and provides multi-language code samples."