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

    Directs the Convert utility to read records from an indexed file
    using a specified key of reference, such as the primary key, the
    first alternate key, or the second alternate key.

    Format

      /KEY=n

    A numeric value that specifies the key of reference that the
    Convert utility uses for reading records from the input indexed
    file. For example, you can specify the primary key as the key of
    reference by using the value 0 (/KEY=0), which is the default, or
    you can specify the first alternate key as the key of reference
    by using the value 1 (/KEY=1). The /KEY qualifier is valid for
    indexed input files only. If you use the /KEY qualifier, you
    must specify a key value (/KEY=0, /KEY=1, and so on). If you do
    not specify the /KEY qualifier, the default is the primary key
    (/KEY=0).