Library /sys$common/syshlp/sda.hlb SET, LOG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 	SET LOG [file-spec]

     Sends a copy of all subsequent output to the file specified.
     In addition, all subsequent output continues to be sent to SYS$OUTPUT.
     If no file is specified, the default file is SYS$OUTPUT.
     This remains in effect until you issue a SET NOLOG command.