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

       /REPLACE
       /NOREPLACE (default)

    Requests that, if a file exists with the same file specification
    as that entered for the output file, the existing file is to
    be deleted. The COPY command allocates new space for the output
    file. In general, when you use the /REPLACE qualifier, include
    version numbers with the file specifications. By default, the
    COPY command creates a new version of a file if a file with
    that specification exists, incrementing the version number. The
    /NOREPLACE qualifier signals an error when a conflict in version
    numbers occurs.