code: public int metaSave(String[] argv, int idx) throws IOException {
      String pathname = argv[idx];
      DistributedFileSystem dfs = getDFS();
      if (dfs == null) {
        System.out.println("FileSystem is " + getFS().getUri());
        return -1;
      }
      dfs.metaSave(pathname);
      System.out.println("Created file " + pathname + " on server " +
                         dfs.getUri());
      return 0;
    }
docs: Dumps DFS data structures into specified file.
  Usage: java DFSAdmin -metasave filename
  @param argv List of of command line parameters.
  @param idx The index of the command that is being processed.
  @exception IOException if an error accoured wile accessing
  the file or path.