Data elements

So far, I've been talking about “data elements” rather than the more familiar term “file.” That's because a directory can contain not just files, but also symbolic links, named special devices, block devices, and so on. I wanted to distinguish between directories and everything elseā€”that's because only directories can have subdirectories and data elements (although symlinks can “appear” to have subdirectories, but that's a topic for later).