/sys$common/syshlp/helplib.hlb ACCOUNTING, /OUTPUT, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The /OUTPUT qualifier creates the specified output file and
    writes the report or copies the selected records to that file.

    If you omit the /OUTPUT qualifier, or you use the /OUTPUT
    qualifier and omit the file specification, the report or selected
    records are output to the current SYS$OUTPUT device.

    If the file specification does not include the device or
    directory name, your current default device or directory is used.
    If you omit the file name, the file name of the first input file
    is used (the first file listed in the parameter to the ACCOUNTING
    command). If you omit the file type, the default file type is
    .LIS if you are producing reports, and .DAT if you are copying
    records.