nix3-build - (unknown subject)

Name  Synopsis  Examples  Description  Options  Common evaluation options  Common flake-related options  Logging-related options  Miscellaneous global options  Options that change the interpretation of installables 

---

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.

•

--no-pretty

Print compact JSON output on a single line, even when the output is a terminal. Some commands may print multiple JSON objects on separate lines.

See `--pretty`.

•

--out-link / -o path

Use path as prefix for the symlinks to the build results. It defaults to result.

•

--pretty

Print multi-line, indented JSON output for readability.

Default: indent if output is to a terminal.

This option is only effective when `--json` is also specified.

•

--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.

Common flake-related options

•

--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.

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.

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 is read from standard input. Implies --impure.

Note

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

---