VMS Help APPEND, Qualifiers, /LOG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /LOG
       /NOLOG (default)

    Controls whether the APPEND command displays the file
    specifications of each file appended. If the /LOG qualifier is
    specified, the command displays the file specifications of the
    input and output files as well as the number of blocks or records
    appended after each append operation.