Back in '70s and early '80s, if you used a computer, you used a command line. DOS -- the disk operating system that runs atop IBM PCs -- used a command line interface, and that's what UNIX used too.

The GUI has served us well for a long time, but it's beginning to fray around the edges. We’re now grappling with an unintended side effect of ubiquitous computing: a surge in complexity that ...