   <p>
                 If the <span class="bold"><strong>-source</strong></span> argument is give, it
                 specifies an underlying flat text database file that is read to
                 initialize a transient record number index.  In the case of variable
                 length records, the records are separated as specified by <span class="bold"><strong>-delim</strong></span>.  For example, standard UNIX byte stream
                 files can be interpreted as a sequence of variable length r