myisamchk error

[Hank]

While running a -rq on a large table, I got the following error:

myisamchk: warning: Duplicate key for record at   54381140 against
record at   54380810


How do I find which record is duplicated (without doing the typical
self-join query)?  This table has 70 million rows, so that's not
really feasible.

myisamchk --block-search # looked promising, but I can't find any
documentation on how to use it properly.

thanks.

-- 

-Hank