So you miss the physical Escape key on your brand new MacBook Pro with Touch Bar? Here's my fix to re-map a seldom used key to Escape.

I like the tactile clickety-clack of physical keyboard - there is something more reassuring about it. But, on the latest MacBook Pro with Touch Bar, the Escape key has been removed in favour of a virtual button on the Touch Bar:

Source: macOS User Guide

The macOS Way: Keyboard Preferences

The simplest option is to re-map a modifier key - Caps Lock, Control, Option, Command or Function key - to Escape.

• Go to System Preferences > Keyboard > Modifier Keys...
• Change a key e.g. Caps Lock to Escape:

For me, this solution is than ideal because my muscle memory demands the top-left most key be Escape, especially when using vi while on auto-pilot. Besides, I don't want to go with the standard modifier keys.

Simple Karabiner Elements Setup

Enter Karabiner Elements 12.1.0: "A powerful and stable keyboard customizer for macOS." With with it I can re-map the top-left-most key to Escape - plus, is free and open source.

On my US keyboard (ANSI) the top-left-most is the "grave accent" ` and "tilde" ~ key:

So to remap this key to Escape:

• After installing, run the Karabiner-Elements.app
• From the Simple Modifications tab, press Add Item
• Then map the From Key grave_accent_and_tilde (`) to the Escape key as shown:

Easy!

Advanced Karabiner Elements Setup

But, that still wasn't good enough for me! The steps above lost me the tilde and grave accent keys, whereas I wanted to maintain:

• ` - Escape
• Shift-` -"tilde" ~ (which is the default behaviour of the key)
• Option-` - "grave accent" to create an accented character e.g. ù
• Command-` - for a normal tick mark `
• Option-Command-` - to open the Force Quit dialog.

I need tilde for things like the Home Directory shortcut (cd ~/Desktop) and the tick mark for Markdown's "double tick".

In Karabiner, this can be done via Complex Modifications, but it requires a bit of code.

• Fire up your editor of choice - I use Visual Studio Code
• Edit ~/.config/karabiner/karabiner.json.
• Under the rules element, add this:

{
    "description": "A Grave Escape",
    "manipulators": [
        {
            "type": "basic",
            "from": 
                { "key_code": "grave_accent_and_tilde" },
            "to": 
                [ { "key_code": "escape" } ]
        },{
            "type": "basic",
            "from": { 
                "key_code": "grave_accent_and_tilde", 
                "modifiers": { "mandatory": [ "command" ] } 
            },
            "to": [ { "key_code": "grave_accent_and_tilde" } ]
        },{
            "type": "basic",
            "from": { 
                "key_code": "grave_accent_and_tilde", 
                "modifiers": { "mandatory": [ "option", "command" ] }
            },
            "to": [ {
                "key_code": "escape",
                "modifiers": [ "option", "command" ]
            } ]
        }
    ]
}

You should get something looking similar to this. For clarity I've intentionally mis-indented it (indents don't matter anyway), plus the screen shot is for a previous version of my code (see the Update below):

• Save, and the Karabiner Elements Complex Modifications tab, you should see the rule loaded. A successful configuration will be reflected in the Log:

[2018-12-18 21:00:00.539] [info] [grabber] Load karabiner.json...
[2018-12-18 21:00:00.540] [info] [grabber] core_configuration is updated.

Now test it!

You can also use the Karabiner-EventViewer.app to monitor the re-mapped keystrokes.

Here I press Escape, then Left Shift-Escape and finally, Fn-Escape:

Hope it helps you get a physical Escape keyboard key while maintaining the keystrokes for ` and ~!

Updated 4 Jan 2019: Changed the script. I realized some lines were not required, and I added code to maintain the Force Quit Applications keystroke.

Updated 11 Jan 2019: Yeesh, missed out the Command modifier keystroke.