SQL & PL/SQL

Good Morning

Can anyone suggest how to include the date into the filename and path
of the spool command.

I have a sheduled process that overrights the spooled output file every time it
runs and I would like to make a new one by making it unique each time


ie)some thing like this
SQL>SPOOL C:\slog_||'(select sysdate from dual)'||.log

thanks


David