fn-toggle

Toggle macOS function-key behavior with a global hotkey.

Press ⌃⌥⌘F to flip your F1–F12 keys between:

• ON — standard function keys (F1, F2, … F12)
• OFF — media / hardware keys (brightness, volume, playback, …)

A notification tells you which mode you just switched to, with a distinct sound for each.

This does exactly what the System Settings → Keyboard → "Use F1, F2, etc. keys as standard function keys" checkbox does — but bound to a key you can hit from anywhere, in any app.

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Why this exists

macOS has no built-in shortcut for that checkbox. The common workaround is an Automator/Shortcuts Quick Action, but binding it to a global hotkey is unreliable (the native "Run with" hotkey often silently fails). fn-toggle skips all that: a tiny shell script driven by skhd, a battle-tested hotkey daemon. No Automator, no Shortcuts.app, no GUI clicking.

How it works

You press ⌃⌥⌘F
      │
      ▼
   skhd (background hotkey daemon)
      │
      ▼
 toggle-function-keys.sh
      │  flips com.apple.keyboard.fnState (0 ⇄ 1)
      │  applies it live via activateSettings -u
      ▼
 notification: "Function Keys: ON / OFF"

The toggle is a plain defaults write to the global com.apple.keyboard.fnState preference, applied immediately (no logout) through Apple's activateSettings helper.

Requirements

• macOS
• Homebrew — the installer offers to install it for you if it's missing

Install

git clone https://github.com/Chromeox/fn-toggle.git
cd fn-toggle
./install.sh

The installer automates the whole setup:

1. Installs Homebrew (with your confirmation) if you don't have it.
2. Installs skhd via Homebrew.
3. Copies the toggle script to ~/.config/fn-toggle/.
4. Adds the hotkey to your ~/.skhdrc (safely — it won't clobber an existing config).
5. Starts the skhd background service.
6. Handles the Accessibility grant for you: opens the right Settings pane, copies the skhd path to your clipboard, then waits and verifies the grant actually took effect.

The one click only you can do: Accessibility access

skhd needs permission to listen for the global hotkey, and macOS requires a human click to grant it (a script can't, by design). The installer makes this as easy as possible — when it reaches this step it will:

• open System Settings → Privacy & Security → Accessibility automatically,
• put the skhd path on your clipboard, and
• wait while you add skhd (click ➕, press ⌘⇧G, paste, Open) and switch it ON.

As soon as you flip the toggle, the installer detects it and finishes. Then press ⌃⌥⌘F and your function keys flip.

Usage

Just press ⌃⌥⌘F any time. A banner confirms the new state.

You can also run the toggle directly, without the hotkey:

~/.config/fn-toggle/toggle-function-keys.sh

Customizing the hotkey

Edit ~/.skhdrc, change the ctrl + alt + cmd - f part to whatever you like, then:

skhd --restart-service

skhd modifier names: cmd, alt (Option), ctrl, shift, fn. Example — make it ⌃⇧F12:

ctrl + shift - f12 : ~/.config/fn-toggle/toggle-function-keys.sh

Troubleshooting

Symptom	Fix
Hotkey does nothing	Grant skhd Accessibility access (see above), then skhd --restart-service.
skhd: must be run with accessibility access! abort.. in logs	Same as above — the permission isn't granted yet.
Toggle works but no notification banner	System Settings → Notifications → Script Editor → allow notifications. Also check you're not in a Focus / Do Not Disturb mode.
Hotkey conflicts with another app	Change the combo in ~/.skhdrc and restart the service.

skhd logs live at /tmp/skhd_<user>.out.log and /tmp/skhd_<user>.err.log.

Uninstall

./uninstall.sh

This removes the hotkey and the installed script. It leaves skhd installed (you might use it for other hotkeys); remove it with brew uninstall skhd.

License

MIT