nixard

A terminal UI to explore NixOS packages, inspect real closure costs, and generate ready-to-use Nix declarations.

Why?

On NixOS, installing a package can pull hundreds of dependencies into the Nix store. Most tools only show the full closure size or the download size — they don't explain:

• what is already available locally
• what actually needs downloading
• how much new disk space will really be used
• which packages are responsible for the largest costs

nixard solves that — interactively.

This tool is aimed at:

• NixOS newcomers trying to understand closures
• advanced users auditing dependency impact
• storage-conscious systems
• anyone who wants to plan installations before committing

Features

• Full terminal UI — keyboard-driven, no mouse needed
• Browse installed packages or search cache.nixos.org candidates
• Real closure analysis — distinguishes packages in your active profile, in the store (GC-able), or fully absent
• Calculates actual additional disk usage and download size
• Concurrent closure crawling via cache.nixos.org for fast analysis
• Flake-aware — detects flake.nix and evaluates scopes accordingly
• Mark packages and export ready-to-use .nixard declaration files
• Export includes environment.systemPackages, home.packages, nix-shell and nix profile install snippets
• Persistent export history with restore and re-export support
• Restore previous selections and extend them with new packages

Installation

Try instantly (without installing)

nix run github:manelinux/nixard

Or enter a temporary shell:

nix shell github:manelinux/nixard

Install permanently

Flake / profile install

nix profile install github:manelinux/nixard

Legacy nix-env

git clone https://github.com/manelinux/nixard.git
cd nixard
nix-env -i -f .

Install from tarball

wget https://github.com/manelinux/nixard/archive/refs/heads/main.tar.gz
tar -xzf main.tar.gz
cd nixard-main
nix-env -i -f .

After installation, launch with:

nixard

Usage

nixard is fully interactive — just launch it and navigate with the keyboard.

Key bindings

Key	Action
↑ ↓	Navigate package list
Space	Mark / unmark package for export
Enter	Select package and inspect closure
e	Open export panel for marked packages
h	Open export history
r	Reload local system data
Esc	Reset to initial state
q	Quit

Scopes (left panel)

nixard shows where each package is present across your system:

Scope	Source
System (active)	/run/current-system — currently active generation
User profile (user)	nix profile install packages for that user
Home Manager (user)	Packages managed via home.packages
Config: system pkgs	Declared in environment.systemPackages
Config: user <name>	Declared in users.users.<name>.packages

Flake-based configurations are detected automatically.

The .nixard export file

When you mark packages and export, nixard generates a .nixard file — a plain text, commented, copy-paste-ready declaration:

# nixard export — "dev-tools"
# Generated: 2026-05-27 23:50
# Packages: 3
#
# Note: download and disk totals shown in the export panel.
# Copy the relevant section into your NixOS configuration.

# ── environment.systemPackages (configuration.nix or flake nixosConfiguration) ──
environment.systemPackages = with pkgs; [
  ripgrep
  fd
  bat
];

# ── home.packages (home-manager home.nix) ──
home.packages = with pkgs; [
  ripgrep
  fd
  bat
];

# ── nix-shell (try without installing) ──
nix-shell -p ripgrep fd bat

# ── nix profile install (per-user installation) ──
nix profile install nixpkgs#ripgrep nixpkgs#fd nixpkgs#bat

Export history is stored at ~/.local/share/nixard/history.json and survives across sessions. You can restore any previous selection, extend it with new packages, and re-export.

How it works

nixard:

• scans /nix/store, the active profile, Home Manager and configuration.nix / flake.nix on startup
• resolves store hashes via nix path-info --derivation + nix show-derivation, with fallback to nix-instantiate
• recursively crawls .narinfo metadata from cache.nixos.org with concurrent requests
• reconstructs the full dependency closure
• compares it against the local store and active profile to compute the real incremental cost

No builds are performed. No system state is modified.

Requirements

• NixOS (or Nix on Linux)
• Python 3
• textual Python library
• Internet access to cache.nixos.org
• Nix experimental features: nix-command flakes (recommended)

Contributing

Pull requests and issues are welcome.

Ideas for future improvements:

• Verify package attribute names against nixpkgs to ensure nixos-rebuild switch compatibility
• --json output mode
• Side-by-side package comparison
• Dependency graph visualization
• --why-depends to trace the heaviest dependency chain
• Local narinfo cache for faster repeated queries
• Tag and filter exports by category

License

MIT