Extracting dat to text files --- appending to existing file

Hi,

I have a task to pull date out from a large table (4GB)
I would be trying different SQL to generte them at diffetent times to a sigle text file.
Here's the sample scritp that I wrote to do it:

set pause off
--set newpage none
set heading off
set pagesize 0
set concat ~
--set feedback off
--set verify off
--set linesize 1000
set trimspool off
set trimout off
set termout off
spool c:\bg1\test1.txt
select PRSBR_ID||'|'||PRSBR_NAME||'|'||PRSBR_ADDR1 from
test1 where prsbr_id='10001'
order by prsbr_name;
spool off

Each time I run this I need to append the data to an already existing text file called test1.txt.
How do we do that.
Could someone send me better scripts to do this ???
THanks,

GEO

Try:

host copy file1 + file2 file1