local f = assert(io.open(arg[1], "rb"))
        local block = 10
        while true do
          local bytes = f:read(block)
          if not bytes then break end
          for b in string.gfind(bytes, ".") do
            io.write(string.format("%02X ", string.byte(b)))
          end
          io.write(string.rep("   ", block - string.len(bytes) + 1))
          io.write(string.gsub(bytes, "%c", "."), "\n")
        end