A lightweight utility that monitors keyboard state on Wayland compositors. It reports keyboard layout changes and lock key states (Caps Lock, Num Lock, Scroll Lock) in real-time.

Tested on labwc.

• libwayland-client - Wayland client library
• libxkbcommon - XKB keyboard handling library
• libxkbregistry - XKB registry for layout lookup (part of libxkbcommon)

• wayland-protocols - Wayland protocol XML files
• wayland-scanner - Wayland protocol code generator
• curl - For downloading wlr-layer-shell protocol

When these optional dependencies are available, xkb-monitor uses wlr-layer-shell to query the current keyboard layout on startup. Without them, the initial layout may default to index 0 until a key is pressed.

# Required
sudo apt install libwayland-dev libxkbcommon-dev

# Optional (for accurate initial layout)
sudo apt install wayland-protocols curl

# Required
sudo pacman -S wayland libxkbcommon

# Optional (for accurate initial layout)
sudo pacman -S wayland-protocols curl

make

This will automatically detect if wayland-protocols and wayland-scanner are available. If found, the build will:

1. Generate xdg-shell protocol files from wayland-protocols
2. Download and generate wlr-layer-shell protocol files
3. Enable accurate initial layout reporting

To explicitly disable layer-shell support even when dependencies are available:

make SKIP_WLR_LAYER_SHELL=1

For a debug build with address sanitizer:

make debug

To clean generated protocol files:

make distclean

Build, then Copy the binary to a directory in your $PATH:

make
sudo cp xkb-monitor /usr/local/bin/

xkb-monitor        # CSV output
xkb-monitor -j     # JSON output
xkb-monitor -n     # Name only (layout changes only)
xkb-monitor -jn    # JSON name only (Waybar compatible)

CSV (default):

index,description,name,variant,caps,num,scroll
0,English (US),us,,0,0,0
1,Greek,gr,,0,0,0

JSON (xkb-monitor -j):

{"index":0,"description":"English (US)","name":"us","variant":"","caps":false,"num":false,"scroll":false}
{"index":1,"description":"Greek","name":"gr","variant":"","caps":false,"num":false,"scroll":false}

Name only (xkb-monitor -n):

us
gr

Name only - JSON (xkb-monitor -jn):

{"text":"us"}
{"text":"gr"}

Add to your Waybar config:

// Alternative: modules-center, or modules-left
"modules-right": [
  ...
  "custom/keyboard-layout",
  ...
],

"custom/keyboard": {
    "exec": "xkb-monitor -n",
    "format": "⌨ {}"
}

To process the output (ie., running sed etc), make sure the tool does not buffer stdout. For example, use sed -u:

"custom/keyboard-layout": {
  "exec": "xkb-monitor -n | sed -u 's/us/e/; s/gr/λ/'",
  "format": "⌨ {}"
}

MIT