My new iPhone 4S arrived on Friday and I’ve been playing with it all weekend. On the surface the 4S looks just like the 4, but it’s what’s inside that sets it apart. It’s faster, it has an incredible camera, and most importantly it ships with Siri. Siri is a voice-controlled personal assistant that lets you use plain language to perform most of the core tasks on the iPhone. You can set reminders and alarms, schedule meetings, get directions, dictate messages and much more, all with your voice. It’s a hands-free, eyes-free way to use your smartphone and it’s a really big deal.

The Command Line Interface Returns

Remember the command line interface (CLI)? Before the popularization of the Graphical User Interface (GUI), computers were controlled by issuing text commands. These commands were often highly efficient, but required users to memorize an endless number of precise instructions in order to get work done. Graphical interfaces made computing more approachable to the average person by introducing visual metaphors to replace complex commands. In many respects, Siri represents a return to the command line interface. The difference is that Siri allows users to speak their commands in natural language. The software interprets these commands and performs the work.

Like the original CLI, voice commands can be incredibly efficient. For example, setting an alarm on my iPhone requires over 15 swipes and taps to complete. I have to unlock the phone, enter my passcode, locate the app, launch it, add an alarm, rotate the dials to set the time and press Done. Using Siri, I simply say: “Wake me up at 6:30 tomorrow morning.” Unlike the CLI, I didn’t need to memorize a command, I just spoke naturally. Here’s what it looks like on the phone:

But I don’t need to see it on my phone because Siri tells me what it’s doing by way of a friendly, slightly robotic voice. We can have a conversation and Siri can even use my previous “commands” to add context to what I say next. For example, I can say “Change it to 7:30” and Siri will know that by “it” I’m referring to the alarm I just set. Your old green screen terminal probably never did anything as cool as that.