Describes key fields, including the position, size, sorting
    order, and data type. Both the position and size of the key field
    must be specified, except for floating point data types where the
    size is known. By default, Sort reorders a file by sorting entire
    records with character data in ascending order. Any other type of
    key field must be specified. When you specify multiple keys, use
    a separate /KEY qualifier for each key.

    Format

      /KEY=(field [,...])