pto_merge can merge several project files to one project file, so that the final project contains every image only once. The same function can be accessed in Hugin by File>Merge project (see Main menu)
Invoke it by
pto_merge -o merged.pto project1.pto project2.pto project3.pto
This will merge the project files project1.pto, project2.pto and project3.pto into a new project file named merged.pto.
If the switch -o or --output is not given, it will add the suffix _merge to the filename of the first project file. So
pto_merge project1.pto project2.pto
will create a merged project file project1_merge.pto.
- pto_merge does not check for duplicate control points. It adds all control points found in the given input files.