Event Command

I wrote ev-cmd because I didn't have an easy way to bind commands to my Koolertron macropad.

Install

NixOS

Add this flake as an input to your NixOS configuration flake:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    ev-cmd = {
      url = "github:danhab99/ev-cmd";  # Update with your GitHub path
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, ev-cmd, ... }: {
    nixosConfigurations.yourhostname = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        {
          environment.systemPackages = [
            ev-cmd.packages.x86_64-linux.default
          ];
        }
      ];
    };
  };
}

Or use it directly with nix run:

nix run github:danhab99/ev-cmd -- --help

Or install it to your profile:

nix profile install github:danhab99/ev-cmd

Arch Linux (AUR)

Install from the AUR using

yay -S ev-cmd

Build from source

Build using cargo build --release

Usage

Basic Usage

ev-cmd listens to input events from a specified device (like a macropad or keyboard) and executes shell commands when keys are pressed.

ev-cmd --device-path /dev/input/by-id/YOUR_DEVICE

Command Line Options

Options:
  -d, --device-path <DEVICE_PATH>  Path to the input device (required)
  -c, --config-path <CONFIG_PATH>  Path to config file (optional)
  -h, --help                       Print help

Configuration

ev-cmd uses a TOML configuration file that maps key codes to shell commands. The program searches for ev-cmd.toml in the following locations (in order):

1. Path specified with --config-path
2. Current working directory (./ev-cmd.toml)
3. User config directory (~/.config/ev-cmd.toml on Linux)
4. /etc/ev-cmd.toml

Configuration File Format

The config file maps evdev key codes to shell commands:

# Key code = "shell command"
30 = "notify-send 'Key A pressed'"
48 = "firefox"
46 = "alacritty"
32 = "rofi -show drun"

Finding Key Codes

To find the key codes for your device:

1. List available input devices:

   ls -l /dev/input/by-id/

2. Run ev-cmd with an empty or minimal config to see key codes:

   ev-cmd --device-path /dev/input/by-id/YOUR_DEVICE

3. Press keys on your device - the program will output:

   Caught keycode 30
   Caught keycode 48
   

4. Use these key codes in your config file

Example Configuration

See templates/ev-cmd.toml.koolertron-ae-smkd for a complete example mapping all keys on a Koolertron macropad.

Example config for common tasks:

# Row 1: Applications
30 = "firefox"
48 = "alacritty"
46 = "code"
32 = "nautilus"

# Row 2: Media controls
35 = "playerctl play-pause"
23 = "playerctl next"
36 = "playerctl previous"
37 = "pactl set-sink-volume @DEFAULT_SINK@ +5%"

# Row 3: System commands
38 = "systemctl suspend"
50 = "loginctl lock-session"
49 = "notify-send 'System Info' \"$(uname -a)\""

# Row 4: Custom scripts
25 = "/home/user/scripts/backup.sh"
16 = "rofi -show run"

Running as a Service

To run ev-cmd automatically on system start, create a systemd user service:

# ~/.config/systemd/user/ev-cmd.service
[Unit]
Description=Event Command Daemon
After=default.target

[Service]
Type=simple
ExecStart=/usr/bin/ev-cmd --device-path /dev/input/by-id/YOUR_DEVICE
Restart=on-failure

[Install]
WantedBy=default.target

Enable and start the service:

systemctl --user enable ev-cmd.service
systemctl --user start ev-cmd.service

Notes

• Only one instance of ev-cmd can run at a time (enforced by PID lock)
• Commands are executed in separate threads, so they don't block event processing
• Only key press events (state = 1) trigger commands; key releases are ignored
• Unmapped keys are silently ignored