declair-rs

declair-rs is a Rust command-line utility that helps you quickly search, add, and manage packages in your NixOS or Home Manager configuration. It can also optionally trigger an automatic rebuild (nixos-rebuild or home-manager switch) after modifying your config.

---

Features

• Search packages using nix search --json and pick a result interactively.
• Insert package into a with pkgs; [ ... ] block (single-line or multi-line).
• Remove packages from that block (via --remove).
• List packages currently present in a config file (--list).
• Create a simple TOML config on first run (~/.config/declair/config.toml).
• Dry-run mode to preview selected package without making changes (--dry-run).
• Support for adding packages as programs.<name>.enable = true; when available (--program).

---

Requirements

• nix (with nix search available)
• nixos-rebuild and/or home-manager if you want automatic rebuilds

---

Install

Run directly from the flake:

nix run github:timasoft/declair-rs

Install permanently to your user profile:

nix profile install github:timasoft/declair-rs

Add as an input to your flake (example):

{
  inputs.declair-rs.url = "github:timasoft/declair-rs";

  outputs = { self, nixpkgs, declair-rs, ... }: {
    nixosConfigurations.my-host = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        ./configuration.nix
        {
          environment.systemPackages = [
            declair-rs.packages.x86_64-linux.default
          ];
        }
      ];
    };
  };
}

---

Usage

declair-rs [OPTIONS]

Common options:

• -c, --config <FILE> — path to config file or directory (overrides stored config)
• -p, --package <NAME> — package name or search query
• -f, fzf — use fzf for package selection (needs fzf installed)
• --no-interactive — run without prompts (fails if required info is missing)
• --no-rebuild — skip automatic rebuild even if enabled in config
• -r, --remove — remove package from the with pkgs; [...] block
• -l, --list — list packages currently present in the with pkgs; [...] block
• -d, --dry-run — perform a dry-run (only print selected package without modifying files)
• --program — use programs.<package>.enable = true; instead of adding pkg to with pkgs; [...] (if available)

Example

Interactive add:

declair-rs
# then type a query like `neovim` and choose a result

Non-interactive (add exact name):

declair-rs --no-interactive -p neovim

List packages in a config:

declair-rs --config /etc/nixos/configuration.nix --list

Remove a package:

declair-rs -c ~/nixos -p somepkg -r

Dry-run to preview selection:

declair-rs -d firefox

Add package as program (when available):

declair-rs -p firefox

---

Configuration

On first run, the tool writes a small TOML config under the platform config dir (typically ~/.config/declair/config.toml).

Example config.toml:

nix_path = "~/nixos"
auto_rebuild = true
home_manager = false
flake = true

Options:

• nix_path — path to your Nix configuration file or directory (tilde ~ is expanded)
• auto_rebuild — whether to run a rebuild after modifying the file
• home_manager — use home-manager switch instead of nixos-rebuild
• flake — append --flake . to rebuild commands

---

Development

Use the provided dev shell (flake):

nix develop

It includes Rust toolchain components: cargo, rustc, rustfmt, clippy, rust-analyzer, and fish shell by default.

Build and run with cargo:

cargo run --release

---

TODO

• Add support for removing packages (--remove).
• Implement listing of currently configured packages (--list).
• Add --dry-run option to preview changes without writing.
• Support programs.<name>.enable = true; style package declarations.
• Support multiple configuration files in a single profile.
• Add autocomplete for package names.
• Add GIF demo to the README