How to add header and trailer to text file using ssis

There is some promise in using the approach in your package. A UNION might accopmplish this if you write your SQL to produce the "exact" same columns. Instead of asking SSIS to build the file lines for you, you would need to create them in your SQL.
For example:
select  1 as rownum, col1 + col2 + cast(sum(col3) as varchar(30)) as fileline from ... (header row)
union all
select 2 as rownum, col3 + col5 + col6 + col9 + col19 + col33 as fileline from ... (detail rows)
union all
select 3 as rownum, .... as fileline from ... (footer / trailer)

Hi,

I am using oledb source in ssis(sql command as data acess mode) to prepare data .How can  I pass
col 2 as variable in header row

Thanks
coventri

You could export a seperate header.txt and trailer.txt file, then use a DOS COPY command to append them all together.
COPY Header.TXT + Data.TXT + Trailer.TXT FinalFile.TXT