Since the XML-based tools are much easier to use than the SGML-based tools, there is no software wrapper like the DocBook-tools around them. The basic utilities can be used directly.
The output formats are:
On a RPM-based system, you will need the following software packages:
DocBook's XML DTD (there's one package per version of the DTD)
Norman Walsh's XSL stylesheets for DocBook
Daniel Veillard's XML library, needed by libxslt
Daniel Veillard's XSLT conversion engine
... or any other Java Runtime Environment, needed by fop
Most of these packages are usually preinstalled with your Linux distribution. For the other ones, use rpm -ih packagename.
You are now ready to edit XML/DocBook documents, then convert them to other formats. To do that, you will need the following commands:
xsltproc: DocBook to HTML or XSL-FO
fop: XSL-FO to PDF, PS, etc.