text: #include <string.h>
  #include <err.h>
  #include "nucleotide_pack.h"
  
  int main(int argc, char* argv[])
  {
      char mode;
      if (argc != 4)
      {
          errx(10, "Wrong number of parameters");
      }
      if (!strcmp(argv[1], "pack"))
      {
          mode = PACK_NUCLEOTIDS;
      }
      else if (!strcmp(argv[1], "unpack"))
      {
          mode = UNPACK_NUCLEOTIDS;
      }
      else
      {
          errx(11, "Unknown mode %s", argv[1]);
      }
      nucleotide_pack(mode, argv[2], argv[3]);
  
      return 0;
  }