Nix command

This article is about the new nix command and all of it's subcommands. The new nix command is intended to unify many different nix utilities that are currently many separate commands, eg. nix-build, nix-shell, etc.

This article is written for nix 2.4 or newer. Older nix versions might have different commands.

Enabling the nix command

In nix 2.4 the nix command must be enabled explicitly set. You can do this in a few different ways.

For an individual invocation, eg.

nix --experimental-features nix-command log ...

Or by setting a user-specific configuration,

# ~/.config/nix/nix.conf
experimental-features = nix-command

in ~/.config/nix/nix.conf.

Or system-wide with

# /etc/nix/nix.conf
{ pkgs, ... }: {
   nix.extraOptions = ''
      experimental-features = nix-command
   '';
   # this is required until nix 2.4 is released
   nix.package = pkgs.nixUnstable;
}

in /etc/nix/nix.conf on NixOS.

Common flags

• --debug enable debug output
• --help show usage information
• --help-config show configuration options
• --log-format FORMAT format of log output; "raw", "internal-json", "bar" or "bar-with-logs"
• --no-net disable substituters and consider all previously downloaded files up-to-date
• --option NAME VALUE set a Nix configuration option (overriding nix.conf)
• -L, --print-build-logs print full build logs on stderr
• --quiet decrease verbosity level
• --refresh consider all previously downloaded files out-of-date
• -v, --verbose increase verbosity level
• --version show version information

In addition, most configuration settings can be overriden using --name value. Boolean settings can be overriden using --name or --no-name. See nix --help-config for a list of configuration settings.

Main commands

nix build

Build a derivation or fetch a store path.

nix develop

Run a bash shell that provides the build environment of a derivation.

nix flake

Manage Nix flakes.

nix profile

Manage Nix profiles.

nix repl

Start an interactive environment for evaluating Nix expressions.

nix run

Run a Nix application.

nix search

Query available packages.

nix shell

Run a shell in which the specified packages are available.

Infrequently used commands

nix copy

Copy paths between Nix stores.

nix edit

Open the Nix expression of a Nix package in $EDITOR.

nix eval

Evaluate a Nix expression.

nix log

Show the build log of the specified packages or paths, if available.

nix path-info

Query information about store paths.

nix registry

Manage the flake registry.

nix verify

Verify the integrity of store paths.

nix why-depends

Show why a package has another package in its closure.

Utility/scripting commands

nix add-to-store

Add a path to the Nix store.

nix cat-nar

Print the contents of a file inside a NAR file on stdout.

nix cat-store

Print the contents of a file in the Nix store on stdout.

nix copy-sigs

Copy path signatures from substituters (like binary caches).

nix dump-path

Dump a store path to stdout (in NAR format).

nix hash-file

Print cryptographic hash of the NAR serialisation of a path.

nix hash-path

Print cryptographic hash of the NAR serialisation of a path.

nix ls-nar

Show information about a path inside a NAR file.

nix ls-store

Show information about a path in the Nix store.

nix make-content-addressable

Rewrite a path or closure to content-addressable form.

nix optimize-store

Replace identical files in the store by hard links.

nix ping-store

Test whether a store can be opened.

nix print-dev-env

Print shell code that can be sourced by bash to reproduce the build environment of a derivation.

nix show-config

Show the Nix configuration.

nix show-derivation

Show the contents of a store derivation.

nix sign-paths

Sign the specified paths.

nix to-base16

Convert a hash to base-16 representation.

nix to-base32

Convert a hash to base-32 representation.

nix to-base64

Convert a hash to base-64 representation.

nix to-sri

Convert a hash to SRI representation.