type         date         name
    ----    ---------------   ------------------------

    file    2023.07.26.1715   Makefile
    file    2023.07.26.1715   obj_io.c
    file    2023.07.26.1715   plyfile.c
    file    2023.10.10.2319   ply.h
    file    2023.07.26.1715   plytest.c