Bootstrap Command Reference

The bootstrap command lets you generate flake.nix, unflake.nix, nixlock.lock.nix, or npins/ from scratch — without being inside an existing flake.

nix-shell https://github.com/vic/flake-file/archive/refs/heads/main.zip \
  -A flake-file.sh --run <app> [--arg <name> <value>]...

Apps

The flake-file.sh shell provides these commands:

App	Description
write-lock	Detect existing lock file and delegate to one of the following as appropriate; requires a lock file already present
write-flake	Generate a flake.nix file
write-inputs	Generate an inputs.nix expression (for debugging)
write-unflake	Generate unflake.nix via unflake
write-nixlock	Generate nixlock.lock.nix via nixlock
write-npins	Generate/update npins/ directory via npins

Arguments

All arguments are passed as --arg <name> <value> to nix-shell.

modules

The Nix file or directory containing your flake-file module definitions. All .nix files in a directory are auto-imported via import-tree.

• Type: path
• Default: [] (empty)

# Single file
--arg modules ./flake-file.nix

# Directory (all .nix files imported)
--arg modules ./modules

bootstrap

Include predefined inputs from the built-in bootstrap.nix. When set to true, all bootstrap inputs are included. When set to a list, only the named inputs are included.

• Type: true | list of input names
• Default: [] (none)

Available bootstrap inputs:

Name	Default URL
import-tree	github:vic/import-tree
flake-file	github:vic/flake-file
flake-parts	github:hercules-ci/flake-parts
nixpkgs	https://channels.nixos.org/nixpkgs-unstable/nixexprs.tar.xz

# Include all bootstrap inputs
--arg bootstrap true

# Include only specific ones
--arg bootstrap '["flake-file" "nixpkgs"]'

Tip

Bootstrap inputs use lib.mkDefault, so your modules can override any of them.

outdir

The directory where generated files are written.

• Type: string
• Default: "."

Important!

Always use --argstr since this value is a string not a Nix Path.

--argstr outdir ./my-project

outputs

Override the flake-file.outputs expression. When not provided, the default from your modules is used.

• Type: null | string (Nix expression)
• Default: null

--argstr outputs 'inputs: inputs.flake-parts.lib.mkFlake { inherit inputs; } (inputs.import-tree ./modules)'

Instead of the above, some special values are recognized: see outputs.nix

--argstr outputs flake-parts