Lack of clarity in description on "svnadmin verify"

[Julian Seward]

Hi.  I'd like to report a lack of clarity in the description of
"svnadmin verify" in the otherwise excellent book.  I have checked 
the latest nightly build of the book (r2744), the FAQ and to some
extent the mailing lists and could not find a clear answer.

The question is very simple.  Periodically I like to check the
backups of our (valgrind.org's) repo using svnadmin verify.  Since I
have no desire to read the entire output, what I do is

  svnadmin verify REPOS_PATH | tail -1

and check that the last line printed, eg

  * Verified revision 6653.

contains a revision number close to what I know is the most recent
revision.

The problem is I don't know what svnadmin does if it finds trouble
and none of the documentation helps.  Does it stop at that point?
Does it print a "this revision is hosed" message and keep going?
In short, if it prints the message above, am I guaranteed that
all revs <= 6653 are OK, or only that 6653 is OK ?

The Book (r2744, p281) says only

  Run this command if you wish to verify the integrity of your
  repository.  This basically iterates through all revisions 
  in the repository by internally dumping all revisions and
  discarding the output.

I think it would help to add a couple of sentences addressing this
point, for the benefit of repo admins like me who want to automate 
verification of their repos.  (Plus I still don't know the answer!)

Specifying a bit more clearly what "verify the integrity"
really means would also be no bad thing.  If svnadmin verify
comes up clean, what does that really tell me?

Thanks

J