Bad Date field

Hello everyone:

Would anyone know how to find a bad date field in an external file?  I have
an external file that I am using to populate a table using the following
command:
COPY release_data FROM '/home/mperalta/release_data' USING DELIMITERS '|'

When I issue this command, the response afte a while is the following:

ERROR; Bad date external representation '9'

The external file is rather large and I've tried finding this bad date
manually with no success.  The table I'm copying into has a datestamp of
type DATE.

Any suggestions would be greatly appreciated.