The OSX Terminal.
The vast majority of Mac owners probably never fire up Terminal.app, which is a pity: some of OSX’s power comes from its BSD underlayer. The command line is your way the core of OSX, and even with underrated tools like Automator available, some tasks are only feasible right at the command line.
Folks who code on Macs, meanwhile, have long known Apple’s Terminal as a nonideal CLI.
Craig Hockenberry begs to differ, offering the most detailed rundown of Terminal’s handy GUI integrations, clever keyboard extensions, and assorted hidden features that I know of. That’s 9,000 very useful words from 2014.
See? The Internet isn’t just a sociopathic hellscape! Only mostly.