As I mentioned in my computational survivalist post, I’m working on a project where I have a dedicated computer with little more than basic Unix tools, ported to Windows. It’s given me a new appreciation for how the standard Unix tools fit together; I’ve had to rely on them for tasks I’d usually do a different way.
I’d seen the nl command before for numbering lines, but I thought, “Why would you ever want to do that? If you want to see line numbers, use your editor.” That way of thinking looks at the tools one at a time, asking what each can do, rather than thinking about how they might work together.