Warning
This program is experimental and its interface is subject to change.

Name

nix build - build a derivation or fetch a store path

Synopsis

nix build [option...] installables...

Examples

Build the default package from the flake in the current directory:
```
# nix build
```

Build and run GNU Hello from the nixpkgs flake:

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

Build GNU Hello and Cowsay, leaving two result symlinks:

# nix build nixpkgs#hello nixpkgs#cowsay
# ls -l result*
lrwxrwxrwx 1 … result -> /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10
lrwxrwxrwx 1 … result-1 -> /nix/store/rkfrm0z6x6jmi7d3gsmma4j53h15mg33-cowsay-3.03+dfsg2

Build GNU Hello and print the resulting store path.

# nix build nixpkgs#hello --print-out-paths
/nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10

Build a specific output:

# nix build nixpkgs#glibc.dev
# ls -ld ./result-dev
lrwxrwxrwx 1 … ./result-dev -> /nix/store/dkm3gwl0xrx0wrw6zi5x3px3lpgjhlw4-glibc-2.32-dev

Build all outputs:

# nix build "nixpkgs#openssl^*" --print-out-paths
/nix/store/gvad6v0cmq1qccmc4wphsazqbj0xzjsl-openssl-3.0.13-bin
/nix/store/a07jqdrc8afnk8r6f3lnhh4gvab7chk4-openssl-3.0.13-debug
/nix/store/yg75achq89wgqn2fi3gglgsd77kjpi03-openssl-3.0.13-dev
/nix/store/bvdcihi8c88fw31cg6gzzmpnwglpn1jv-openssl-3.0.13-doc
/nix/store/gjqcvq47cmxazxga0cirspm3jywkmvfv-openssl-3.0.13-man
/nix/store/7nmrrad8skxr47f9hfl3xc0pfqmwq51b-openssl-3.0.13

Build attribute build.x86_64-linux from (non-flake) Nix expression release.nix:
```
# nix build --file release.nix build.x86_64-linux
```

Build a NixOS system configuration from a flake, and make a profile point to the result:

# nix build --profile /nix/var/nix/profiles/system \
    ~/my-configurations#nixosConfigurations.machine.config.system.build.toplevel

(This is essentially what nixos-rebuild does.)

Build an expression specified on the command line:

# nix build --impure --expr \
    'with import <nixpkgs> {};
     runCommand "foo" {
       buildInputs = [ hello ];
     }
     "hello > $out"'
# cat ./result
Hello, world!

Note that --impure is needed because we're using <nixpkgs>, which relies on the $NIX_PATH environment variable.

Fetch a store path from the configured substituters, if it doesn't already exist:
```
# nix build /nix/store/rkfrm0z6x6jmi7d3gsmma4j53h15mg33-cowsay-3.03+dfsg2
```

Description

nix build builds the specified installables. Installables that resolve to derivations are built (or substituted if possible). Store path installables are substituted.

Unless --no-link is specified, after a successful build, it creates symlinks to the store paths of the installables. These symlinks have the prefix ./result by default; this can be overridden using the --out-link option. Each symlink has a suffix -<N>-<outname>, where N is the index of the installable (with the left-most installable having index 0), and outname is the symbolic derivation output name (e.g. bin, dev or lib). -<N> is omitted if N = 0, and -<outname> is omitted if outname = out (denoting the default output).

Options

--dry-run

Show what this command would do without doing it.
--json

Produce output in JSON format, suitable for consumption by another program.
--no-link

Do not create symlinks to the build results.
--out-link / -o path

Use path as prefix for the symlinks to the build results. It defaults to result.
--print-out-paths

Print the resulting output paths
--profile path

The profile to operate on.
--rebuild

Rebuild an already built package and compare the result to the existing store paths.
--stdin

Read installables from the standard input. No default installable applied.

Common evaluation options

--arg name expr

Pass the value expr as the argument name to Nix functions.
--arg-from-file name path

Pass the contents of file path as the argument name to Nix functions.
--arg-from-stdin name

Pass the contents of stdin as the argument name to Nix functions.
--argstr name string

Pass the string string as the argument name to Nix functions.
--debugger

Start an interactive environment if evaluation fails.
--eval-store store-url

The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.
--impure

Allow access to mutable paths and repositories.
--include / -I path

Add path to search path entries used to resolve lookup paths

This option may be given multiple times.

Paths added through -I take precedence over the nix-path configuration setting and the NIX_PATH environment variable.
--override-flake original-ref resolved-ref

Override the flake registries, redirecting original-ref to resolved-ref.

--commit-lock-file

Commit changes to the flake's lock file.
--inputs-from flake-url

Use the inputs of the specified flake as registry entries.
--no-registries

Don't allow lookups in the flake registries.

DEPRECATED

Use --no-use-registries instead.
--no-update-lock-file

Do not allow any updates to the flake's lock file.
--no-write-lock-file

Do not write the flake's newly generated lock file.
--output-lock-file flake-lock-path

Write the given lock file instead of flake.lock within the top-level flake.
--override-input input-path flake-url

Override a specific flake input (e.g. dwarffs/nixpkgs). This implies --no-write-lock-file.
--recreate-lock-file

Recreate the flake's lock file from scratch.

DEPRECATED

Use nix flake update instead.
--reference-lock-file flake-lock-path

Read the given lock file instead of flake.lock within the top-level flake.
--update-input input-path

Update a specific flake input (ignoring its previous entry in the lock file).

DEPRECATED

Use nix flake update instead.

--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.

Miscellaneous global 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.
--repair

During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
--version

Show version information.

Options that change the interpretation of installables

--expr expr

Interpret installables as attribute paths relative to the Nix expression expr.
--file / -f file

Interpret installables as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression will be read from standard input. Implies --impure.

Note

See man nix.conf for overriding configuration settings with command line flags.

Nix Reference Manual