hwdb udev Keyboard remap

hwdb udev keyboard.sh

# Original reference https://yulistic.gitlab.io/2017/12/linux-keymapping-with-udev-hwdb/

systemd --version | head -n1 | awk '{print $2}'

# note systemd versions below 220 need
# keyboard:usb:v*p*
# 220 and above
# evdev:name:<name>:*

cat /proc/bus/input/devices

cat /proc/bus/input/devices | grep -B1 keyboard | head -n1
cat /proc/bus/input/devices | grep -B1 keyboard | head -n1 | cut -c 8- | perl -p -e 's/(.\w+\=)/,/g'

// Grab all before match for multiple keyboards
cat /proc/bus/input/devices | awk '/eyboard/{for(i=2;i<=x;)print a[i++]}{for(i=1;i<x;i++)a[i]=a[i+1];a[x]=$0;}' x=2 | head -n2

// Grab all after match for multiple keyboards
cat /proc/bus/input/devices | awk '/eyboard/{nr[NR+4]}; NR in nr' | awk -F"event" '/event/{print $2}' | head -n2

awk '/eyboard/{for(i=1;i<=x;)print a[i++];print}{for(i=1;i<x;i++)a[i]=a[i+1];a[x]=$0;}'
cat /proc/bus/input/devices | awk '/eyboard/{for(i=2;i<=x;)print a[i++];print}{for(i=1;i<x;i++)a[i]=a[i+1];a[x]=$0;}' x=2
cat /proc/bus/input/devices | awk '/eyboard/{for(i=2;i<=x;)if(i % 2 == 0){print a[i++];print}}{for(i=1;i<x;i++)a[i]=a[i+1];a[x]=$0;}' x=2

cat /proc/bus/input/devices | grep -A2 keyboard | tail -n1 | awk '{print substr($0,length($0),1)}'

I: Bus=0011 Vendor=0001 Product=0001 Version=ab83
N: Name="AT Translated Set 2 keyboard"
P: Phys=isa0060/serio0/input0
S: Sysfs=/devices/platform/i8042/serio0/input/input2
U: Uniq=
H: Handlers=sysrq kbd leds event2 
B: PROP=0
B: EV=120013
B: KEY=402000000 3803078f800d001 feffffdfffefffff fffffffffffffffe
B: MSC=10
B: LED=7

sudo evtest /dev/input/event2

evdev:input:b<bus_id>v<vendor_id>p<product_id>e<version_id>-<modalias>

// Built in keyboard
I: Bus=0011 Vendor=0001 Product=0001 Version=ab83
// USB Keyboard - HOLTEK USB-HID Keyboard
I: Bus=0003 Vendor=04d9 Product=a131 Version=0111


sudo vim /etc/udev/hwdb.d/99-keyboard.hwdb
-------------------------
// GUI mode

// Chromebook
evdev:input:b0011v0001p0001*
  KEYBOARD_KEY_1d=leftalt
  KEYBOARD_KEY_38=leftctrl
  KEYBOARD_KEY_db=leftmeta

// USB keyboard
evdev:name:HOLTEK USB-HID Keyboard:*
  KEYBOARD_KEY_700e0=leftmeta
  KEYBOARD_KEY_700e3=leftalt
  KEYBOARD_KEY_700e2=leftctrl

-----------------------------------
// Remote macOS mode

// Chromebook
evdev:input:b0011v0001p0001*
  KEYBOARD_KEY_1d=leftalt
  KEYBOARD_KEY_38=leftmeta
  KEYBOARD_KEY_db=leftctrl

// USB keyboard
evdev:name:HOLTEK USB-HID Keyboard:*
  KEYBOARD_KEY_700e0=leftctrl
  KEYBOARD_KEY_700e3=leftalt
  KEYBOARD_KEY_700e2=leftmeta
  
-----------------------------------

// Normal Mode

// Chromebook
evdev:input:b0011v0001p0001*
  KEYBOARD_KEY_1d=leftctrl
  KEYBOARD_KEY_38=leftalt
  KEYBOARD_KEY_db=leftmeta

// USB keyboard
evdev:name:HOLTEK USB-HID Keyboard:*
  KEYBOARD_KEY_700e0=leftctrl
  KEYBOARD_KEY_700e3=leftmeta
  KEYBOARD_KEY_700e2=leftalt

-----------------------------

sudo systemd-hwdb update
sudo udevadm trigger

-----------------------
KEYBOARD_KEY_<scan_code>=<key_code>

    Event code 29 (KEY_LEFTCTRL)
    Event code 56 (KEY_LEFTALT)
    Event code 97 (KEY_RIGHTCTRL)
    Event code 100 (KEY_RIGHTALT)
    Event code 125 (KEY_LEFTMETA)
    Event code 126 (KEY_RIGHTMETA)
    Event code 127 (KEY_COMPOSE)