You can specify a display with -m for the “main” display or -d and an integer to target a specific display by number (as returned in the -l listing). To set a new brightness, just call brightness with a float between 0 and 1 as an argument, e.g.

The current display brightness is returned as a float (decimal) between 0 and 1, so 0.5 is half brightness, and 1 is full. Usable for desktop GUI, uses OpenGL accelerationĭisplay 1: active, awake, online, built-in, ID 0x4280886 IOKit flags 0x2000007 IOKit display mode ID 0x80003000 Once installed, you can use brightness -l to query all displays for basic info:ĭisplay 0: main, active, awake, online, external, ID 0x4248798 It can query all displays for current brightness levels (and other info) and modify the brightness on any or all displays from the command line.īrightness can be installed with Homebrew: brew install brightness will do the trick. It took a while to find a CLI called brightness by Nicholas Riley, but it’s a perfect fix. To script it, you have to open System Preferences and use accessibility scripting to actually move the slider, which I refuse to do on principle.

The thing is, unlike system volume, there’s no System Events API for display brightness. But with the PowerMate on my desktop, I developed a curiosity. With BetterTouchTool and my Ultimate Hacking Keyboard I have Fn-M and Fn-N assigned to simultaneously increase and decrease the brightness on both of my MacBook Pro display and my external Thunderbolt Display, which is generally satisfactory. Which means I slog to my computer in the dark, and coming out of a pitch black room means adjusting my monitor brightness more than “automatically adjust brightness” will accommodate. Meanwhile, I keep waking up too early and being unable to fall back asleep 2. For various reasons, I’d replaced it with my Shuttle Xpress on my desk, but I found space to comfortably use both and set about re-configuring the actions on it. While I did upgrade to the Bluetooth version, I still like the USB one better 1. After talking about it with the panel on a recent Mac Show appearance (pretty sure this part of the conversation happened during technical difficulties), I pulled out my Griffin PowerMate.

Adjust brightness mac external display