Hammerspoon and Karabiner-Elements are all you need for a frictionless OSX experience

I use two tools to massively boost my productivity while working on OSX. This article describes my configuration and how you can customize it to your own needs.

Hammerspoon is an incredibly powerful wrapper around OSX, allowing you to easily interact with the OS via scripting, such as trigger notifications, move and resize windows, open applications, etc.

Karabiner-Elements is a keyboard customization tool. I use this to remap keys to make it simple to trigger my Hammerspoon scripts from the keyboard.

Features

  • position - Instantly resize windows into halves of your screen
  • focus - Shift focus (i.e. click) onto an app, or launch if not open
  • monitor - Move windows between external monitors or spaces
  • gcal - Menu bar to see all of your upcoming calendar events
  • timer - Pomodoro timer to keep you focused

Position

Window positioning module borrowed from Miro Mannino.

  • hyper + right resizes window to right side of screen.
  • hyper + left resizes window to left side of screen.
  • hyper + up resizes window to upper side of screen.
  • hyper + down resizes window to bottom side of screen.

Repeated presses of the above will cycle half, quarter, and 2/3 of screen.

hyper + enter resizes window to entire screen

Repeated presses of hyper + enter will cycle through resizing similarly.

Focus

File containing hotkey bindings. Each segment binds a hotkey to a useful application - such as hyper + c to launch Chrome

Monitor

Keybindings used to interact with an external monitor, or between spaces within a monitor. Very useful for moving applications back and forth.

  • hyper + shift + right cycles the current application to monitor on the right
  • hyper + shift + left cycles the current application to monitor on the left
  • hyper + shift + h moves the current application to a space on the left
  • hyper + shift + l moves the current application to a space on the right

gcal

Constructs a menubar. Uses the Google Calendar API to fetch events, colors, timing, etc. to a json file, which are then loaded into the menubar on each refresh.

timer

A simple pomodoro timer! Sets a default time for 25 minutes, with option to pause and cancel.

How to use

Karabiner-Elements

Karabiner-Elements is a relatively new tool made when OSX Sierra came out. As a result, installing it is a bit of a hassle as it’s still under continuous development. Follow the instructions in the How to Build section in the link above. It requires installing C++ Boost Libraries, XCode Build tools beforehand but should compile into a standalone application, which doesn’t need to be compiled every time you update.

edit: it can now be downloaded directly as a package!

Use Karabiner to make a hyper key. I rebinding my caps lock key (which I never use) into ctrl+alt+cmd. Do this by editing your karabiner.json file located in ~/.config/karabiner. See my file here that you can copy/paste

Hammerspoon

Download the latest release. I recommend familiarizing with it through the getting started guide here.

Hammerspoon interacts with the operating system using the Lua language, which is an easy to learn scripting language. Whenever hammerspoon is loaded or refreshed, your ~/.hammerspoon/init.lua file is processed. You can use the console as a REPL for lua code.

To start, I defined the hyperkey

init.lua

hyper = {"ctrl", "alt", "cmd"}

and followed the docs to build the focusing hotkey

focus.lua

    hs.hotkey.bind(hyper, "C", function ()
      hs.application.launchOrFocus('Google Chrome')
    end)
    
    hs.hotkey.bind(hyper, 'E', function ()
      hs.application.launchOrFocus('Visual Studio Code')
    end)

The file focus.lua is separate from init.lua. To activate this code, all I need to do is include focus.lua

init.lua

require('focus')

Hammerspoon has a great community that have built a ton of other spoons and sample configurations. For instance, I borrowed the fantastic resizing hotkey functionality from another user.