In this book you will learn how to use Hammerspoon, a powerful open-source framework which makes using a Mac more pleasant, productive and fun. It enables interaction with the system at multiple layers—from low-level file system or network access, mouse or keyboard event capture and generation, all the way to manipulating applications or windows, processing URLs and drawing on the screen. It also allows interfacing with AppleScript, the most common mechanism for automation on the Mac. Hammerspoon configuration is written in Lua, a popular embedded programming language.

Using Hammerspoon, you can replace many stand-alone Mac utilities for controlling or customizing specific aspects of your Mac (those that tend to overcrowd the menubar). Here are some examples of things you can do with it:

• Add missing or more convenient keyboard shortcuts to applications, even for complex multi-step actions. For example: automated tagging and filing in Evernote, mail archival in Mail or Outlook, filing items from multiple applications to OmniFocus using consistent keyboard shortcuts, or muting/unmuting a conversation in Skype.
• Manipulate windows using keyboard shortcuts to resize, move and arrange them.
• Dispatch URLs to different browsers based on regular expression patterns. When combined with Site-specific Browsers, this allows for highly flexible management of bookmarks, plugins and search configurations.
• Replace Spotlight, Lacona and other launchers with a fully configurable, extensible launcher, which allows not only to open applications, files and bookmarks, but to trigger arbitrary Lua functions.
• Set up actions to happen automatically when switching between WiFi networks—for example, for reconfiguring proxies in some applications.
• Keyboard-triggered translation of selected text between arbitrary human languages.
• Keep a configurable and persistent clipboard history.
• Automatically pause audio playback when headphones are unplugged.

In this book you will learn how to get started with Hammerspoon, how to use pre-made modules, and how to write your own, to achieve an unprecedented level of control over your Mac.