System Configuration (modules/core/system/default.nix)

The system config file located at modules/core/system/default.nix serves as the core system configuration for your nixri setup. It manages Nix settings, localization, package manager defaults, and essential environment variables.

Structure

The file is structured to define global settings and services. It inherits variables from your host-specific variables.nix (such as keyboard layout and console keymap) to apply them system-wide.

1. Programs and Services

This section enables essential programs and background services.

  • nix-index-database.comma: Enabled to allow running programs without installing them using the , (comma) command.
  • gnupg.agent: Enables the GnuPG agent, including SSH support, for managing keys securely.
  • services.xserver: While nixri is Wayland-based (Hyprland), basic xserver configuration is provided to ensure tools like localectl work correctly by exporting the XKB configuration (keyboard layout and variant).

2. Nix Package Manager Settings

This section heavily configures how Nix operates on your system.

  • settings:
    • download-buffer-size: Increased to 200000000 to prevent issues when downloading large files.
    • auto-optimise-store: Enabled to automatically hardlink identical files in the Nix store, saving disk space at the cost of slightly longer rebuild times.
    • substituters & trusted-public-keys: Defines external binary caches (like NixOS, nix-community, chaotic-nyx, nix-gaming, and hyprland) to speed up package installations by downloading pre-built binaries instead of compiling from source.
    • experimental-features: Enables modern Nix features, specifically nix-command and flakes.
  • optimise.automatic: Schedules automatic Nix store optimization.
  • package: Uses the latest version of Nix (pkgs.nixVersions.latest).

3. Time and Localization

This section defines your regional settings.

  • time.timeZone: Sets the system timezone (e.g., "Asia/Kolkata").
  • i18n: Configures the default locale (en_US.UTF-8) and extra locale settings (like formatting for address, time, monetary values) to a specific region (e.g., "en_IN").

4. Environment Variables

Defines critical environment variables that are loaded early during the boot/login process.

  • NIXOS_OZONE_WL: Set to "1" to force Electron apps to use Wayland natively.
  • XDG Base Directories: Explicitly defines standard directories (XDG_CACHE_HOME, XDG_CONFIG_HOME, XDG_DATA_HOME, XDG_BIN_HOME, XDG_RUNTIME_DIR) to prevent race conditions during load order, ensuring user configurations and data are placed correctly.

5. Nixpkgs and State Version

  • console.keyMap: Sets the TTY keymap based on variables.nix.
  • nixpkgs.overlays: Applies all defined overlays to modify or extend packages.
  • nixpkgs.config.allowUnfree: Enabled (true) to allow the installation of proprietary software (like NVIDIA drivers, Discord, Steam).
  • system.stateVersion: Indicates the NixOS release version the system was initially installed with. CRITICAL: Do not change this value, as it manages stateful data compatibility.

How to Apply Changes

Changes made to this file require a system rebuild to take effect. Run your system rebuild script or nixos-rebuild command to apply the new system-wide configurations.