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

    The /KEY qualifier specifies all the necessary information about
    a key field. If the file is to be sorted using entire records
    with character data in ascending order, you do not need to
    specify the key information.

    When a key field must be described, you must specify both the
    position and the size of the key. In addition, if the sorting
    or merging operation is to be done in descending alphabetic or
    numeric order, specify DESCENDING in the key description.

    If the data in the key fields is not character data, you must
    specify the data type. The following data types are recognized by
    the Sort/Merge utility:

       BINARY, [SIGNED]
       BINARY, UNSIGNED
       CHARACTER
       DECIMAL, LEADING_SIGN, SEPARATE_SIGN [SIGNED]
       DECIMAL, LEADING_SIGN, [OVERPUNCHED_SIGN, SIGNED]
       DECIMAL [,SIGNED, TRAILING_SIGN, OVERPUNCHED_SIGN]
       DECIMAL, [TRAILING SIGN], SEPARATE_SIGN, [SIGNED]
       DECIMAL, UNSIGNED
       D_FLOATING
       F_FLOATING
       G_FLOATING
       H_FLOATING
       PACKED_DECIMAL
       S_FLOATING (Alpha only)
       T_FLOATING (Alpha only)
       ZONED

    The items in brackets are defaults and need not be specified.

    Multiple Keys

    You can specify up to 255 key fields in a sorting operation. If
    you do specify multiple keys, decide which is primary, which is
    secondary, and so on; then, in the command string, list them in
    the order of their priority.

    By default, Sort assigns 1 to the first key specified in the
    command line, 2 to the second key, and so on. If you do not list
    the keys in the order of their priority, specify the order of
    each with the parameter NUMBER:n.

    For each Sort key, you must use a separate /KEY qualifier.
    If Sort finds /KEY parameters repeated after a single /KEY
    qualifier, it does not treat these as specifications for multiple
    keys; instead, the duplicate parameters override previously
    specified parameters.