kb-remap

Tool to assist remapping macOS keyboard keys.

🚀 Getting started

Install the tool using Cargo.

cargo install kb-remap

🤸 Usage

Running the tool without any options will list the available HID devices.

$ kb-remap --list

Vendor ID  Product ID  Name
---------  ----------  ----------------------------------
0x0        0x0         BTM
0x0        0x0         Headset
0x4c       0x269       Magic Mouse
0x5ac      0x342       Apple Internal Keyboard / Trackpad
0x5ac      0x342       Keyboard Backlight
0xc45      0x7692      USB Keyboard
0x1050     0x407       YubiKey OTP+FIDO+CCID

Usually it's pretty simple to pick out which devices are keyboards. Using the name listed above as --name you can remap any key you want using the --map or --swap options. For example the following remaps capslock to backspace and swaps § (section) and ` (backtick) on a the internal macOS keyboard.

$ kb-remap --name "Apple Internal Keyboard / Trackpad" --map capslock:delete --swap '0x64:`'

You can reset the mapping using:

$ kb-remap --name "Apple Internal Keyboard / Trackpad" --reset

If you want you can inspect the raw hidutil command that would be run for a particular command using the --dump option.

$ kb-remap --name "Apple Internal Keyboard / Trackpad" --map capslock:delete --dump

Would output the following:

hidutil property \
    --matching '{"VendorID":1452,"ProductID":834}' \
    --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":30064771129,"HIDKeyboardModifierMappingDst":30064771114}]}'

Specifying keys

The --map and --swap options both expect the source and destination keys to be specified and separated by a ":" (colon).

There are three ways to specify keys:

Name

Some keys you can specify using their name. For example the Return (Enter) key "⏎" can be specified as "return". These are added on a convenience basis.

Additionally, the following special names are available and map multiple keys if they are used.

Character

Most typeable keys can be specified using their character. For example: the A key can be specified using "A" or "a". The USB usage ID used will the one that the key corresponds to on a US keyboard.

Number

Any key can be specified by using the USB usage ID in decimal or hex. For example: Z has a usage ID of "29", which can also be specified as "0x1d".

🤔 Why? How?

Powerful applications to remap macOS keys like Karabiner-Elements are often overkill for simple remappings. Additionally, they can sometimes take a while to support the latest macOS version. I wanted a simple reliable solution.

Instead of a constantly running application kb-remap simply subprocesses to the built-in macOS hidutil command to fetch keyboard information and to remap keys. This remapping does not persist if keyboards are unplugged or if your Mac goes to sleep. kb-remap does not solve this problem for you yet. One option is to install a launchd service to automatically run kb-remap.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.