Name¶

nix - a tool for reproducible and declarative configuration management

Synopsis¶

nix [option…] subcommand

where subcommand is one of the following:

Main commands:

• nix build (./nix3-build.md) - build a derivation or fetch a store path

• nix develop (./nix3-develop.md) - run a bash shell that provides the build environment of a derivation

• nix flake (./nix3-flake.md) - manage Nix flakes

• nix help (./nix3-help.md) - show help about nix or a particular subcommand

• nix profile (./nix3-profile.md) - manage Nix profiles

• nix repl (./nix3-repl.md) - start an interactive environment for evaluating Nix expressions

• nix run (./nix3-run.md) - run a Nix application

• nix search (./nix3-search.md) - search for packages

• nix shell (./nix3-shell.md) - run a shell in which the specified packages are available

Infrequently used commands:

• nix bundle (./nix3-bundle.md) - bundle an application so that it works outside of the Nix store

• nix copy (./nix3-copy.md) - copy paths between Nix stores

• nix edit (./nix3-edit.md) - open the Nix expression of a Nix package in $EDITOR

• nix eval (./nix3-eval.md) - evaluate a Nix expression

• nix fmt (./nix3-fmt.md) - reformat your code in the standard style

• nix log (./nix3-log.md) - show the build log of the specified packages or paths, if available

• nix path-info (./nix3-path-info.md) - query information about store paths

• nix registry (./nix3-registry.md) - manage the flake registry

• nix why-depends (./nix3-why-depends.md) - show why a package has another package in its closure

Utility/scripting commands:

• nix daemon (./nix3-daemon.md) - daemon to perform store operations on behalf of non-root clients

• nix describe-stores (./nix3-describe-stores.md) - show registered store types and their available options

• nix hash (./nix3-hash.md) - compute and convert cryptographic hashes

• nix key (./nix3-key.md) - generate and convert Nix signing keys

• nix nar (./nix3-nar.md) - create or inspect NAR files

• nix print-dev-env (./nix3-print-dev-env.md) - print shell code that can be sourced by bash to reproduce the build environment of a derivation

• nix realisation (./nix3-realisation.md) - manipulate a Nix realisation

• nix show-config (./nix3-show-config.md) - show the Nix configuration

• nix show-derivation (./nix3-show-derivation.md) - show the contents of a store derivation

• nix store (./nix3-store.md) - manipulate a Nix store

Commands for upgrading or troubleshooting your Nix installation:

• nix doctor (./nix3-doctor.md) - check your system for potential problems and print a PASS or FAIL for each check

• nix upgrade-nix (./nix3-upgrade-nix.md) - upgrade Nix to the latest stable version

Examples¶

•

Create a new flake:

# nix flake new hello
# cd hello

•

Build the flake in the current directory:

# nix build
# ./result/bin/hello
Hello, world!

•

Run the flake in the current directory:

# nix run
Hello, world!

•

Start a development shell for hacking on this flake:

# nix develop
# unpackPhase
# cd hello-*
# configurePhase
# buildPhase
# ./hello
Hello, world!
# installPhase
# ../outputs/out/bin/hello
Hello, world!

Description¶

Nix is a tool for building software, configurations and other artifacts in a reproducible and declarative way. For more information, see the Nix homepage (https://nixos.org/) or the Nix manual (https://nixos.org/manual/nix/stable/).

Installables¶

Many nix subcommands operate on one or more installables. These are command line arguments that represent something that can be built in the Nix store. Here are the recognised types of installables:

•

Flake output attributes: nixpkgs#hello

These have the form flakeref[#attrpath], where flakeref is a flake reference and attrpath is an optional attribute path. For more information on flakes, see the nix flake manual page (./nix3-flake.md). Flake references are most commonly a flake identifier in the flake registry (e.g. nixpkgs), or a raw path (e.g. /path/to/my-flake or . or ../foo), or a full URL (e.g. github:nixos/nixpkgs or path:.)

When the flake reference is a raw path (a path without any URL scheme), it is interpreted as a path: or git+file: url in the following way:

Note that the search will only include files indexed by git. In particular, files which are matched by .gitignore or have never been git add-ed will not be available in the flake. If this is undesirable, specify path:<directory> explicitly;

For example, if /foo/bar is a git repository with the following structure: . └── baz ├── blah │  └── file.txt └── flake.nix

Then /foo/bar/baz/blah will resolve to git+file:///foo/bar?dir=baz

For example, if /foo/bar/flake.nix exists, then /foo/bar/baz/ will resolve to path:/foo/bar

If attrpath is omitted, Nix tries some default values; for most subcommands, the default is packages.system.default (e.g. packages.x86_64-linux.default), but some subcommands have other defaults. If attrpath is specified, attrpath is interpreted as relative to one or more prefixes; for most subcommands, these are packages.system, legacyPackages.*system* and the empty prefix. Thus, on x86_64-linux nix build nixpkgs#hello will try to build the attributes packages.x86_64-linux.hello, legacyPackages.x86_64-linux.hello and hello.

•

Store paths: /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10

These are paths inside the Nix store, or symlinks that resolve to a path in the Nix store.

•

Store derivations: /nix/store/p7gp6lxdg32h4ka1q398wd9r2zkbbz2v-hello-2.10.drv

Store derivations are store paths with extension .drv and are a low-level representation of a build-time dependency graph used internally by Nix. By default, if you pass a store derivation to a nix subcommand, it will operate on the output paths of the derivation. For example, nix path-info prints information about the output paths:

# nix path-info --json /nix/store/p7gp6lxdg32h4ka1q398wd9r2zkbbz2v-hello-2.10.drv
[{"path":"/nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10",…}]

If you want to operate on the store derivation itself, pass the --derivation flag.

•

Nix attributes: --file /path/to/nixpkgs hello

When the -f / --file path option is given, installables are interpreted as attribute paths referencing a value returned by evaluating the Nix file path.

•

Nix expressions: --expr '(import <nixpkgs> {}).hello.overrideDerivation (prev: { name = "my-hello"; })'.

When the --expr option is given, all installables are interpreted as Nix expressions. You may need to specify --impure if the expression references impure inputs (such as <nixpkgs>).

For most commands, if no installable is specified, the default is ., i.e. Nix will operate on the default flake output attribute of the flake in the current directory.

Nix stores¶

Most nix subcommands operate on a Nix store.

TODO: list store types, options

Options¶

• --help
  Show usage information.
• --offline
  Disable substituters and consider all previously downloaded files up-to-date.
• --option name value
  Set the Nix configuration setting name to value (overriding nix.conf).
• --refresh
  Consider all previously downloaded files out-of-date.
• --version
  Show version information.

Logging-related options:

• --debug
  Set the logging verbosity level to ‘debug’.
• --log-format format
  Set the format of log output; one of raw, internal-json, bar or bar-with-logs.
• --print-build-logs / -L
  Print full build logs on standard error.
• --quiet
  Decrease the logging verbosity level.
• --verbose / -v
  Increase the logging verbosity level.

Options to override configuration settings:

• --accept-flake-config
  Enable the accept-flake-config setting.
• --access-tokens value
  Set the access-tokens setting.
• --allow-dirty
  Enable the allow-dirty setting.
• --allow-import-from-derivation
  Enable the allow-import-from-derivation setting.
• --allow-new-privileges
  Enable the allow-new-privileges setting.
• --allow-symlinked-store
  Enable the allow-symlinked-store setting.
• --allow-unsafe-native-code-during-evaluation
  Enable the allow-unsafe-native-code-during-evaluation setting.
• --allowed-impure-host-deps value
  Set the allowed-impure-host-deps setting.
• --allowed-uris value
  Set the allowed-uris setting.
• --allowed-users value
  Set the allowed-users setting.
• --auto-optimise-store
  Enable the auto-optimise-store setting.
• --bash-prompt value
  Set the bash-prompt setting.
• --bash-prompt-suffix value
  Set the bash-prompt-suffix setting.
• --build-hook value
  Set the build-hook setting.
• --build-poll-interval value
  Set the build-poll-interval setting.
• --build-users-group value
  Set the build-users-group setting.
• --builders value
  Set the builders setting.
• --builders-use-substitutes
  Enable the builders-use-substitutes setting.
• --commit-lockfile-summary value
  Set the commit-lockfile-summary setting.
• --compress-build-log
  Enable the compress-build-log setting.
• --connect-timeout value
  Set the connect-timeout setting.
• --cores value
  Set the cores setting.
• --diff-hook value
  Set the diff-hook setting.
• --download-attempts value
  Set the download-attempts setting.
• --enforce-determinism
  Enable the enforce-determinism setting.
• --eval-cache
  Enable the eval-cache setting.
• --experimental-features value
  Set the experimental-features setting.
• --extra-access-tokens value
  Append to the access-tokens setting.
• --extra-allowed-impure-host-deps value
  Append to the allowed-impure-host-deps setting.
• --extra-allowed-uris value
  Append to the allowed-uris setting.
• --extra-allowed-users value
  Append to the allowed-users setting.
• --extra-experimental-features value
  Append to the experimental-features setting.
• --extra-extra-platforms value
  Append to the extra-platforms setting.
• --extra-hashed-mirrors value
  Append to the hashed-mirrors setting.
• --extra-ignored-acls value
  Append to the ignored-acls setting.
• --extra-nix-path value
  Append to the nix-path setting.
• --extra-platforms value
  Set the extra-platforms setting.
• --extra-plugin-files value
  Append to the plugin-files setting.
• --extra-sandbox-paths value
  Append to the sandbox-paths setting.
• --extra-secret-key-files value
  Append to the secret-key-files setting.
• --extra-substituters value
  Append to the substituters setting.
• --extra-system-features value
  Append to the system-features setting.
• --extra-trusted-public-keys value
  Append to the trusted-public-keys setting.
• --extra-trusted-substituters value
  Append to the trusted-substituters setting.
• --extra-trusted-users value
  Append to the trusted-users setting.
• --fallback
  Enable the fallback setting.
• --filter-syscalls
  Enable the filter-syscalls setting.
• --flake-registry value
  Set the flake-registry setting.
• --fsync-metadata
  Enable the fsync-metadata setting.
• --gc-reserved-space value
  Set the gc-reserved-space setting.
• --hashed-mirrors value
  Set the hashed-mirrors setting.
• --http-connections value
  Set the http-connections setting.
• --http2
  Enable the http2 setting.
• --ignored-acls value
  Set the ignored-acls setting.
• --impersonate-linux-26
  Enable the impersonate-linux-26 setting.
• --keep-build-log
  Enable the keep-build-log setting.
• --keep-derivations
  Enable the keep-derivations setting.
• --keep-env-derivations
  Enable the keep-env-derivations setting.
• --keep-failed
  Enable the keep-failed setting.
• --keep-going
  Enable the keep-going setting.
• --keep-outputs
  Enable the keep-outputs setting.
• --log-lines value
  Set the log-lines setting.
• --max-build-log-size value
  Set the max-build-log-size setting.
• --max-free value
  Set the max-free setting.
• --max-jobs value
  Set the max-jobs setting.
• --max-silent-time value
  Set the max-silent-time setting.
• --min-free value
  Set the min-free setting.
• --min-free-check-interval value
  Set the min-free-check-interval setting.
• --nar-buffer-size value
  Set the nar-buffer-size setting.
• --narinfo-cache-negative-ttl value
  Set the narinfo-cache-negative-ttl setting.
• --narinfo-cache-positive-ttl value
  Set the narinfo-cache-positive-ttl setting.
• --netrc-file value
  Set the netrc-file setting.
• --nix-path value
  Set the nix-path setting.
• --no-accept-flake-config
  Disable the accept-flake-config setting.
• --no-allow-dirty
  Disable the allow-dirty setting.
• --no-allow-import-from-derivation
  Disable the allow-import-from-derivation setting.
• --no-allow-new-privileges
  Disable the allow-new-privileges setting.
• --no-allow-symlinked-store
  Disable the allow-symlinked-store setting.
• --no-allow-unsafe-native-code-during-evaluation
  Disable the allow-unsafe-native-code-during-evaluation setting.
• --no-auto-optimise-store
  Disable the auto-optimise-store setting.
• --no-builders-use-substitutes
  Disable the builders-use-substitutes setting.
• --no-compress-build-log
  Disable the compress-build-log setting.
• --no-enforce-determinism
  Disable the enforce-determinism setting.
• --no-eval-cache
  Disable the eval-cache setting.
• --no-fallback
  Disable the fallback setting.
• --no-filter-syscalls
  Disable the filter-syscalls setting.
• --no-fsync-metadata
  Disable the fsync-metadata setting.
• --no-http2
  Disable the http2 setting.
• --no-impersonate-linux-26
  Disable the impersonate-linux-26 setting.
• --no-keep-build-log
  Disable the keep-build-log setting.
• --no-keep-derivations
  Disable the keep-derivations setting.
• --no-keep-env-derivations
  Disable the keep-env-derivations setting.
• --no-keep-failed
  Disable the keep-failed setting.
• --no-keep-going
  Disable the keep-going setting.
• --no-keep-outputs
  Disable the keep-outputs setting.
• --no-preallocate-contents
  Disable the preallocate-contents setting.
• --no-print-missing
  Disable the print-missing setting.
• --no-pure-eval
  Disable the pure-eval setting.
• --no-require-sigs
  Disable the require-sigs setting.
• --no-restrict-eval
  Disable the restrict-eval setting.
• --no-run-diff-hook
  Disable the run-diff-hook setting.
• --no-sandbox
  Disable sandboxing.
• --no-sandbox-fallback
  Disable the sandbox-fallback setting.
• --no-show-trace
  Disable the show-trace setting.
• --no-substitute
  Disable the substitute setting.
• --no-sync-before-registering
  Disable the sync-before-registering setting.
• --no-trace-function-calls
  Disable the trace-function-calls setting.
• --no-use-case-hack
  Disable the use-case-hack setting.
• --no-use-registries
  Disable the use-registries setting.
• --no-use-sqlite-wal
  Disable the use-sqlite-wal setting.
• --no-warn-dirty
  Disable the warn-dirty setting.
• --plugin-files value
  Set the plugin-files setting.
• --post-build-hook value
  Set the post-build-hook setting.
• --pre-build-hook value
  Set the pre-build-hook setting.
• --preallocate-contents
  Enable the preallocate-contents setting.
• --print-missing
  Enable the print-missing setting.
• --pure-eval
  Enable the pure-eval setting.
• --relaxed-sandbox
  Enable sandboxing, but allow builds to disable it.
• --repeat value
  Set the repeat setting.
• --require-sigs
  Enable the require-sigs setting.
• --restrict-eval
  Enable the restrict-eval setting.
• --run-diff-hook
  Enable the run-diff-hook setting.
• --sandbox
  Enable sandboxing.
• --sandbox-build-dir value
  Set the sandbox-build-dir setting.
• --sandbox-dev-shm-size value
  Set the sandbox-dev-shm-size setting.
• --sandbox-fallback
  Enable the sandbox-fallback setting.
• --sandbox-paths value
  Set the sandbox-paths setting.
• --secret-key-files value
  Set the secret-key-files setting.
• --show-trace
  Enable the show-trace setting.
• --stalled-download-timeout value
  Set the stalled-download-timeout setting.
• --store value
  Set the store setting.
• --substitute
  Enable the substitute setting.
• --substituters value
  Set the substituters setting.
• --sync-before-registering
  Enable the sync-before-registering setting.
• --system value
  Set the system setting.
• --system-features value
  Set the system-features setting.
• --tarball-ttl value
  Set the tarball-ttl setting.
• --timeout value
  Set the timeout setting.
• --trace-function-calls
  Enable the trace-function-calls setting.
• --trusted-public-keys value
  Set the trusted-public-keys setting.
• --trusted-substituters value
  Set the trusted-substituters setting.
• --trusted-users value
  Set the trusted-users setting.
• --use-case-hack
  Enable the use-case-hack setting.
• --use-registries
  Enable the use-registries setting.
• --use-sqlite-wal
  Enable the use-sqlite-wal setting.
• --user-agent-suffix value
  Set the user-agent-suffix setting.
• --warn-dirty
  Enable the warn-dirty setting.