/sys$common/syshlp/helplib.hlb UIL, /LIST[=file-spec]  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Negative form:  /NOLIST

  Controls whether the compiler produces a listing file.  The  default
  output file type is .LIS.

  /LIST is the batch default and /NOLIST is the interactive default.