Gedcom DataBase Interface, or GDBI, is a genealogy program integrator. It includes an editor and the lifelines report language. It interfaces to 3 GEDCOM databases: phpGedView, GenJ, and jLifelines. At the core is a common Java API to simplify adding more databases and editors.
Comment by Dick Eastman: If the above paragraph doesn't make sense to you, I'd suggest that GDBI is not for you. It is a software tool for use by experienced software and database experts.
GDBI is written in Java. It has been tested on Windows, Linux and several versions of UNIX. It should also work on other operating systems that fully support Java.
The latest release of GDBI adds an import feature for reading in another GEDCOM file. It also has fixes for the merge feature added in the previous release. Import and merge are similar in that they both involve a second GEDCOM file. Import is the relatively simple process of adding everything from the second file. A merge requires finding overlapping people in the two GEDCOM files, and it allows you to select how much of the second GEDCOM to read in.
More information about GDBI is available at: http://gdbi.sourceforge.net