PressAndHold hacked plist

PressAndHold is a neat MacOSX feature that let's you do a long press and get a little menu with accent options for a character.

You can get it up and running by using the command

defaults write -g ApplePressAndHoldEnabled -bool true

Since the accent list is in a .plist file, you can edit it to change or extend the characters offered.

I have done just that here. This .plist file provides

1. 𝔹𝕝𝕒𝕔𝕜𝕓𝕠𝕒𝕣𝕕 bold letters and digits - digits are handled by the key right underneath (in QWERTY) - so to get a 𝟛 you'll press and hold E. You also get ℼ, ℿ, ⅀, ℽ and ℾ.
2. Superscript digits, placed together with the blackboard bold digits.
3. More greek letters. You can usually get µ and π easily, and I know how to also get ∑ and Ω straightforwardly. But this gives press and hold access to
   • 𝜔, 𝜛 (on w)
   • 𝜀, 𝜂 (on e)
   • 𝜌, 𝜚 (on r)
   • 𝜏, 𝜃, 𝜗 (on t)
   • 𝜄 (on i)
   • 𝜓 (on p)
   • 𝛼 (on a)
   • 𝜎 and ς (on s)
   • 𝛿 (on d)
   • 𝜑 and 𝜙 (on f)
   • 𝛾 (on g)
   • ϰ (on k)
   • 𝜆 (on l)
   • 𝜁 (on z)
   • 𝜉 and 𝜒 (on x)
   • 𝛽 (on b) as well as
   • 𝛩 (on T)
   • ∏ and 𝛹 (on P)
   • ∑ (on S)
   • 𝛷 (on F)
   • 𝛤 (on G)
   • 𝛬 (on L)
   • 𝛯 (on X)
4. Arrows! Since S had a lot of letters assigned, arrows are
   • a/A - ←⇐↚↢↞↤
   • w/W - ↑⇑↥⤉↟
   • d/D - →⇒↛↣↠↦
   • x/X - ↓⇓↧⤈↡ (not S - we don't get WASD arrows alas)
   • s/S - ↔︎⇔
5. A few miscellaneous useful symbols hiding under q/Q - ∀∃∄ℵ∝

To use this, find out where your computer has PressAndHold.app. On High Sierra, this is in /System/Library/Input Methods/. Inside the app (which is actually a directory), there is a directory with a lot of .plist files. It used to - on earlier versions - be in PressAndHold.app/Contents/Resources if I remember correctly. On High Sierra, the .plist definitions can be found in PressAndHold.app/Contents/PlugIns/PAH_Extension.appex/Contents/Resources.

1. Back up the file Keyboard-en.plist. It's probably possible to recover it, but don't take any risks here...
2. If on High Sierra or later, shut off SIP (system integrity protection):
   • Reboot
   • Hold Cmd+R as you boot it up. This gets you into rescue mode
   • Open a terminal
   • Run csrutil disable - this removes the integrity protection, making system files readable. This protection is there to protect from malicious software going in and messing with your system - but also stops you from messing with your system
   • Reboot
3. Copy this Keyboard-en.plist into the directory holding all the .plist files
4. Test it immediately to make sure nothing's gone wrong
5. Reenable SIP by:
   • Reboot
   • Hold Cmd+R as you boot it up. This gets you into rescue mode
   • Open a terminal
   • Run csrutil enable
   • Reboot