Mac OSX Window Management with Hammerspoon

Hammerspoon is a really powerful but simple automation tool for OSX.

Below, I show the Lua script that I use to make Hammerspoon my basic OSX keyboard controlled window manager to move and resize windows easily.

What it looks like

Note: The key bindings are only showing for demonstration purposes. Those overlays won’t show for you.

The Hammerspoon Script

-- GRID
hs.window.animationDuration=0.2
local hotkey = require "hs.hotkey"
local grid = require "hs.grid"

grid.MARGINX = 20
grid.MARGINY = 20
grid.GRIDHEIGHT = 4
grid.GRIDWIDTH = 6

local mod_resize = {"ctrl", "cmd"}
local mod_move = {"ctrl", "alt"}

-- Move Window
hotkey.bind(mod_move, 'j', grid.pushWindowDown)
hotkey.bind(mod_move, 'k', grid.pushWindowUp)
hotkey.bind(mod_move, 'h', grid.pushWindowLeft)
hotkey.bind(mod_move, 'l', grid.pushWindowRight)

-- Resize Window
hotkey.bind(mod_resize, 'k', grid.resizeWindowShorter)
hotkey.bind(mod_resize, 'j', grid.resizeWindowTaller)
hotkey.bind(mod_resize, 'l', grid.resizeWindowWider)
hotkey.bind(mod_resize, 'h', grid.resizeWindowThinner)

How to use

It’s pretty self explanatory from the code above, but you can customize the animation duration and the grid sizing to your liking.

Note: to make these modifier keys more ergonomic, I recommend remapping your Caps Lock key to Control. You can do so in System Preferences -> Keyboard -> Modifier Keys.

Hotkeys:

Ctrl + Opt + j : Move window down
Ctrl + Opt + k : Move window up
Ctrl + Opt + h : Move window left
Ctrl + Opt + l : Move window right

Ctrl + Cmd + j : Resize window down
Ctrl + Cmd + k : Resize window up
Ctrl + Cmd + h : Resize window left
Ctrl + Cmd + l : Resize window right