Mac: How to Create Keyboard Layout and Keybinding

By Xah Lee. Date: 2007-12-30. Last updated: 2015-12-23.

This page tells you how to modify Mac OS X's keybinding.

You can:

Define your own keys for cursor movement and editing commands.
Define 【⌥ option+letter】 key to insert your favorite unicode characters or math symbols. 〔➤see Unicode Characters ☯ ☭ ⚡ ∑ ♀ ♂ ♥ 😄〕

mac unicode char — Mac OS X, 【`⌥ option`+`key`】 in Dvorak Keyboard Layout

Key Config File

Create a file at ~/Library/KeyBindings/DefaultKeyBinding.dict. Create the “KeyBindings” dir if you don't already have it.

The DefaultKeyBinding.dict file is just a text file.

The file's content should be key ＆ action pairs, like this:

/* this is comment */
{
"keycode1" = actionCode1;
"keycode2" = actionCode2;
}

Keycode is a string that represents key press.
actionCode represents what to do.

Simple Example

Create a file at ~/Library/KeyBindings/DefaultKeyBinding.dict, and put the following content.

/* -*- coding: utf-8 -*- */
/* my keybindings */

{
/* insert Unicode character with Option key down*/
"~a" = ("insertText:", "\U03B1"); /* greek alpha α */
"~;" = ("insertText:", "\U2665"); /* heart symbol ♥ */

/* move cursor with i j k l keys while Ctrl key down */
"^i" = ("moveUp:");
"^k" = ("moveDown:");
"^j" = ("moveLeft:");
"^l" = ("moveRight:");
}

Restart a application and the new keybinding will take effect in that application. Launch TextEdit to test your changes.

Note: Only applications that uses Cocoa Text System will support this.

Note: if you use Unicode Characters directly in the file such as →, you must save the file using UTF-8 encoding.

Key Syntax

Mac OS X Keybinding Key Syntax

Action Code

Mac OS X Keybinding Action Code

Sample File

Example of defining the {↖ Home, ↘ End} keys to move to the beginning/end of line.

/* make home/end key to move to begin/end of line */

{
"\UF729" = "moveToBeginningOfLine:"; /* home key */
"\UF72B" = "moveToEndOfLine:"; /* end key */
}

Here's example file for inserting Unicode characters with the ⌥ option key.

/* -*- coding: utf-8 -*- */
{

/* insert Unicode characteres with Option key down */
"~#8" = ("insertText:", "↑");
"~#2" = ("insertText:", "↓");
"~#4" = ("insertText:", "←");
"~#6" = ("insertText:", "→");

"~a" = ("insertText:", "α");
"~h" = ("insertText:", "θ");

"~3" = ("insertText:", "†");
"~7" = ("insertText:", "—");
"~8" = ("insertText:", "•");
"~9" = ("insertText:", "★");

"~&" = ("insertText:", "‣");
"~*" = ("insertText:", "°");

/* insert pairs with Option down */
"~d" = ("insertText:", "«»", "moveBackward:");
"~h" = ("insertText:", "{}", "moveBackward:");
"~t" = ("insertText:", "()", "moveBackward:");
"~n" = ("insertText:", "[]");
"~s" = ("insertText:", "“”", "moveBackward:");
"~-" = ("insertText:", "「」", "moveBackward:");

"~D" = ("insertText:", "‹›", "moveBackward:");
"~S" = ("insertText:", "‘’", "moveBackward:");
"~_" = ("insertText:", "『』", "moveBackward:");

/* insert sig */
"~1" = ("insertText:", "  John\n http://example.com/\n\n☄");
}

Here's a example of ErgoEmacs Keybinding, one for QWERTY layout and one for Dvorak Keyboard Layout:

You can look at Xcode's keybinding file at /Developer/Applications/Xcode.app/Contents/Resources/PBKeyBinding.dict. You can view it here: osx_keybinding_xcode.dict.txt.

Emacs Keybinding

Mac OS X by default support emacs' keybindings. They are:

Mac OS X's default emacs keybindings
Key	Action
【`Ctrl`+`f`】	move forward
【`Ctrl`+`b`】	move backward
【`Ctrl`+`n`】	move down a line
【`Ctrl`+`p`】	move up a line
【`Ctrl`+`a`】	beginning of line
【`Ctrl`+`e`】	end of line
【`Ctrl`+`k`】	delete current position to end of line
【`Ctrl`+`y`】	paste

You can add more of emacs's

Key	Action
【`Ctrl`+`space`】	set mark
【`Ctrl`+`w`】	cut
【`Ctrl`+`x` `Ctrl`+`x`】	Swap cursor position to last mark

However, i don't recommend it. Emacs's keys is very inefficient and ergonomically painful. See: Why Emacs's Keyboard Shortcuts are Painful. If you like a efficient keybinding for text editing, you might try: ErgoEmacs Keybinding.

Problems

See: Problems of Mac OS X's Keybinding Scheme DefaultKeyBinding.dict.

Alternatives

Something DefaultKeyBinding.dict can't do. For example:

It cannot remap keys.
It can't set a key such as F8 to type other keys such as 【⌘ command+c】.
It can't set a key to launch a app or script.

There are many solutions to these. See:

Mac: Key Remapping, Keybinding Tools

Best is to get a programable keyboard. I can recommend Logitech G910 Orion Spark Keyboard. May look ugly, but is functionally the best keyboard. Quiet mechanical keys.

logitech g910 keyboard 12 — Logitech G910 Orion Spark Keyboard amazon

logitech g710plus keyboard — Logitech G710+ Mechanical Keyboard amazon

References

Text System Defaults and Key Bindings By Apple. @ https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/EventOverview/TextDefaultsBindings/TextDefaultsBindings.html
Apple Doc. NSResponder Class Reference By Apple. @ https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSResponder_Class/index.html
Customizing the Cocoa Text System 2006-03 By Jacob Rus. @ http://www.hcs.harvard.edu/~jrus/Site/cocoa-text.html
Technical Note TN2056: Installable Keyboard Layouts @ https://developer.apple.com/library/mac/technotes/tn2056/_index.html

Note: the default keybinding config file used by the system is a XML file at: /System/Library/Frameworks/AppKit.framework/Resources/StandardKeyBinding.dict. You don't have to do anything with that file. This is for your information only.