How to assign a keyboard shortcut to just the Command key on Mac OS

Question

Coming from linux (KDE) I was able to assign a keyboard shortcut to the meta key. I'm wondering if it's possible to do something similar with the Command key on macOS? I would like to open launchpad after a single press of the Command key ideally.

Answer 1

You can do it with Karabiner-Elements using Complex Modifications.

There is no such modification in the Karabiner-Elements complex_modifications rules list so you will have to add it manually:

0. Install and setup Karabiner-Elements.
1. Open ~/.config/karabiner/karabiner.json.
2. Add the following rule in profiles.complex_modifications.rules list:

{
    "description": "Open Launchpad if left_command is pressed alone.",
    "manipulators": [
        {
            "type": "basic",
            "from": {
                "key_code": "left_command",
                "modifiers": {
                    "optional": [
                        "any"
                    ]
                }
            },
            "to": [
                {
                    "key_code": "left_command"
                }
            ],
            "to_if_alone": [
                {
                    "shell_command": "open -a Launchpad.app"
                }
            ]
        }
    ]
}

3. Save the changes. The rule should appear in Karabiner-Elements UI as shown in the picture below: