spool sends the output that is normally written to the console also to a file or printer, or (spool off) turns this additional output off. .lst (or .lis on some systems). set termout off prevents printing output to the console, which is especially useful while spooling to a file. spool.sql and spool_off.sql are two SQL scripts for $SQLPATH that modify SQL*Plus settings in a way that spool creates clean output.