When I’m out of the office and running my Mac on batteries, I turn off Bluetooth networking to save power. Then I come into the office and plug in. I use my MacBook with its lid shut. I plug into a keyboard and a monitor. I have a Bluetooth Magic Trackpad. Great set up. The problem is that—with the lid shut and Bluetooth turned off, I have no mouse or pointer control. I need to turn Bluetooth on using just the keyboard.
So I press ⌘-Space on my keyboard to bring up Spotlight¹.
I select the Bluetooth File Exchange program. Bluetooth is off. So the first thing that program does is prompt me: “Bluetooth Hardware is Off. In order to use this application, the Bluetooth hardware must be on. Do you want to turn it on?". Thankfully, “Turn Bluetooth On” is highlighted.
I just press Enter to turn on Bluetooth. After a second or two, it finds my trackpad and we’re good to go. I have to quit the Bluetooth File Exchange, but I don’t have to open and shut my lid.
¹ Ok, actually I use Quicksilver, which everyone should use. But Spotlight works for this.