Using Caps Lock as Esc in Mac OS X

Since macOS 10.12.1 it is possible to remap Caps Lock to Esc natively (System Preferences -> Keyboard -> Modifier Keys).

I wasn't happy with any of the answers here, and went looking for a command-line solution.

In macOS Sierra 10.12, Apple introduced a new way for users to remap keys.

• No need to fiddle around with system GUIs
• No special privileges are required
• Completely customisable
• No need to install any 3rd-party crap like PCKeyboardHack / Seil / Karabiner / KeyRemap4MacBook / DoubleCommand / NoEjectDelay

If that sounds good to you, take a look at hidutil.

For example, to remap caps-lock to escape, refer to the key table and find that caps-lock has usage code 0x39 and escape has usage code 0x29. Put these codes or'd with the hex value 0x700000000 in the source and dest like this:

hidutil property --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x700000039,"HIDKeyboardModifierMappingDst":0x700000029}]}'

You may add other mappings in the same command. Personally, I like to remap caps-lock to backspace, and remap backspace to delete:

hidutil property --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x700000039,"HIDKeyboardModifierMappingDst":0x70000002A}, {"HIDKeyboardModifierMappingSrc":0x70000002A,"HIDKeyboardModifierMappingDst":0x70000004C}]}'

To see the current mapping:

hidutil property --get "UserKeyMapping"

Your changes will be lost at system reboot. If you want them to persist, configure them in a launch agent. Here's mine:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<!-- Place in ~/Library/LaunchAgents/ -->
<!-- launchctl load com.ldaws.CapslockBackspace.plist -->
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>com.ldaws.CapslockEsc</string>
    <key>ProgramArguments</key>
    <array>
      <string>/usr/bin/hidutil</string>
      <string>property</string>
      <string>--set</string>
      <string>{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x700000039,"HIDKeyboardModifierMappingDst":0x70000002A},{"HIDKeyboardModifierMappingSrc":0x70000002A,"HIDKeyboardModifierMappingDst":0x70000004C}]}</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
  </dict>
</plist>

I've placed this content into a file located at ~/Library/LaunchAgents/com.ldaws.CapslockBackspace.plist and then executed:

launchctl load com.ldaws.CapslockBackspace.plist

The only thing I know how to do is to map Caps Lock to Control, or Option, or Command. This can be done via the Keyboard & Mouse pane of System Preferences. Click on "Modifier Keys" on the bottom left and you'll be able to remap Caps Lock, Control, Option, and Command, to any of those.

@Craig: This suggests that Caps Lock can be used as a normal -- that is, non-toggle -- key. On my MacBook, since I have re-mapped Caps Lock to Control, the Caps Lock light never lights up. It simply acts like the Control key.

It's possible.

Solution 1

From an arcticle on TrueAffection.net.

• Download PCKeyboardHack and install it.
• Go to PCKeyboardHack in System Preferences.
• Enable ‘Change Caps Lock’ and set the keycode to 53.

Solution 2

This solution doesn't involve patching the keyboard driver, but gives you a Vim specific solution.

OS X supports mapping the Caps Lock key to a whole bunch of keys, but you have to do it 'by hand', editting .plist files. The process is described in this article. As addendum to that hint I suggest you first set Caps-Lock to None in the System Preferences, then you only need to change one value in the .plist file. Also, you can of course use the Property List Editor instead of going through the XML conversion steps.

The trick is to map the Caps Lock key to the Help key (code 6), which isn't on most keyboards. But if it is, it will be treated as the insert key, which you probably don't use anyway, since you ask about remapping your Caps Lock to prevent stretching your hands ;)

You can then map the Help and the Insert key to Esc in vim.

map  <Help> <Esc>
map! <Help> <Esc>
map  <Insert> <Esc>
map! <Insert> <Esc>

This will work for gvim (Vim.app). I didn't get it to work with vim in the Terminal and I haven't tested it with MacVim.

So, it's rather a complicated, half-baked solution or installing a third-party piece of hackery. Your pick ;)

Edit: Just noticed solution 3, if you're using MacVim you can use Ctrl, Option and Command as Esc. With the System Preferences it's trivial to map Caps Lock to one of those keys.

Having tried several of these solutions, I have some notes:

DoubleCommand will not allow you to swap esc and caps-lock.

PCKeyboardHack will allow you to map capslock to escape, but does not have the capability to map escape to capslock. Recent versions will allow you to perform a complete swap by editing both keys.

This may or may not be sufficient for your needs (I know it is for mine).

Seil doesn't work on macOS Sierra yet, so I'm using Karabiner Elements, download from https://pqrs.org/latest/karabiner-elements-latest.dmg.

Either use the GUI or put the following into ~/.karabiner.d/configuration/karabiner.json:

{
  "profiles" : [
    {
      "name" : "Default profile",
      "selected" : true,
      "simple_modifications" : {
        "caps_lock" : "escape"
      }
    }
  ]
}

You can also use DoubleCommand to remap this, and other keys.

IIRC, it will map Caps Lock to Esc.

Karabiner-Elements A powerful and stable keyboard customizer for macOS. (freeware)

https://pqrs.org/osx/karabiner/index.html

Worked for me for Mojave to change caps-lock to backspace