Question : Trigger to extract bytea or blob object after it's inserted

I have a table that stores files as bytea type.  I'd like to have a trigger function (if it's possible) to extract the file after it's inserted inserted and store it on disk.  Does anyone have an example of this?  Are there any caveats to doing this?

Answer : Trigger to extract bytea or blob object after it's inserted

sorry, am not that great at postgre either, so i forgot some few things :P
ignore my previous comments.

' It is now just exporting everything.  I'd like it to export only the file that had just been imported, so basically the filename.
'
replace " FOR EACH STATEMENT" - this does call procedure for all rows
with "for each row" - calls procedure for any new,updated row
 
http://www.postgresql.org/docs/8.1/interactive/sql-createtrigger.html