Проверка времени эпохи UNIX в MATLAB

Попробуйте добавить параметр -U .

На странице руководства:

   -U
   --packet-buffered
          If  the  -w option is not specified, make the printed packet output ``packet-buffered''; i.e., as the description of the contents of each packet is printed, it will be written to the standard
          output, rather than, when not writing to a terminal, being written only when the output buffer fills.

      If the -w option is specified, make the saved raw packet output ``packet-buffered''; i.e., as each packet is saved, it will be written to the output file, rather than being written only  when
      the output buffer fills.

      The -U flag will not be supported if tcpdump was built with an older version of libpcap that lacks the pcap_dump_flush() function.