"This month we'll look at ways to build those database-like
systems. Some of these techniques are so specific that
they’re intended more as examples (an idea of what’s
possible) than as specific solutions to everyday problems.
If you won't be using the filesystem as a database, you might
still be interested in the ways we stretch the shells and
utilities. You'll see curly-brace and arithmetic evaluation
operators, along with printf(1), to build whole directory trees
with just a few commands. We'll also use the almost-forgotten (but
useful!) bc and jot utilities."