To create the GNU/Linux Command-Line Tools Summary, I used LyX, the document processor. To convert the LyX files to DocBook SGML I used the lyxtox Scripts created by Chris Karakas.
You may also want to check out the db2lyx package, created by Dr. B Guillion, which can be used to convert LyX files to XML DocBook and XML DocBook back to LyX.
I also had assistance from various The Linux Documentation Project volunteers (see the contributors section Section 1.7 for specific details).