C:\wepos>svnadmin create one

C:\wepos>svnadmin create two

C:\wepos>set ROOT=file:///c:/wepos

C:\wepos>svn mkdir %ROOT%/one/trunk -m "One trunk"

Committed revision 1.

C:\wepos>svn mkdir %ROOT%/two/trunk -m "Two trunk"

Committed revision 1.

C:\wepos>svnadmin dump one > one.dmp
* Dumped revision 0.
* Dumped revision 1.

C:\wepos>svnadmin dump two > two.dmp
* Dumped revision 0.
* Dumped revision 1.

C:\wepos>svndumptool.py merge -i one.dmp -i two.dmp -o out.dmp
Revision: 1        from r1        one.dmp
Revision: 2        from r1        two.dmp
created 2 revisions

C:\wepos>svnadmin create three

C:\wepos>svnadmin load three < out.dmp
<<< Started new transaction, based on original revision 1
     * adding path : trunk ... done.

------- Committed revision 1 >>>

<<< Started new transaction, based on original revision 2
     * adding path : trunk ...svnadmin: File already exists: filesystem 'three\d
b', transaction '1-1', path 'trunk'

C:\wepos>