Use stable PUBLIC identifiers in your DOCTYPE declarations in your files, and not worry about using the SYSTEM identifier to find the DTD file or system entity files. The PUBLIC identifier can be mapped to a specific location on a given machine with a catalog. If you move your files to a new machine, you do not have to edit them all to change the SYSTEM reference, you just edit the catalog's mapping of the PUBLIC identifier.

Write Makefiles with generic pathnames to your stylesheet, and let the catalog remap the pathname to a location on the machine. When you move your setup and files to a different machine or to different locations, you do not have to fix internal references in your documents, stylesheets, and Makefiles. You can just use a catalog file to map the generic paths to the new locations.

Use stable Internet URL addresses for your DTD system identifier or stylesheet pathname, but let the catalog resolve them to pathnames on the local machine. That way you get efficient processing if they are available locally, and it falls back to network access only if it has to.

Select a different stylesheet for the same command by selecting a different catalog file that maps the pathname to a different location. For example, you could put docbook.xsl on all your command lines in your Makefiles, then have the Makefile map that to, say, chunk.xsl stylesheet if a variable is set.

Test new releases of the stylesheets or DTD by temporarily changing your catalog to point to them.