nix3-build

builds derivations from flakes

TLDR

Build the default package of a flake in the current directory

$ nix build

Build a specific output of the current flake

$ nix build .#[package]

Build from nixpkgs

$ nix build nixpkgs#[hello]

Build without creating a result symlink

$ nix build --no-link

Build and print full build logs

$ nix build -L [installable]

Build and print output store paths

$ nix build --print-out-paths [installable]

Dry-run without actually building

$ nix build --dry-run [installable]

SYNOPSIS

nix build [options] [installable...]

nix build (invoked as nix3-build in this manual namespace to distinguish it from the legacy nix-build) builds the specified installables, which may be flake references, attribute paths, or store paths. On success it creates a symlink named result (or result-N for additional outputs) pointing to the build output in the Nix store.When multiple installables are given, each is built in parallel subject to the configured build concurrency.

PARAMETERS

INSTALLABLE

Flake reference, attribute path, or store path to build (e.g. .#default, nixpkgs#hello).

--no-link

Do not create a result symlink.

-o PATH, --out-link PATH

Use PATH as the prefix for the result symlink (default: result).

--rebuild

Rebuild an already-built derivation and compare outputs.

--print-out-paths

Print the resulting store paths to stdout.

-L, --print-build-logs

Show full build logs on standard error.

--json

Print build results as JSON.

--dry-run

Show what would be built or fetched without actually doing it.

--impure

Allow evaluation of impure expressions (e.g. references to environment variables).

--refresh

Consider all previously downloaded files as stale.

--help

Display help information.

CAVEATS

Part of the new nix CLI; requires the nix-command and flakes experimental features to be enabled (via nix.conf or --extra-experimental-features). Behavior may change between Nix releases.

HISTORY

nix3 refers to the Nix 3.x CLI, with build being the primary compilation command.