nix3-build(1)

    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/10l19qifk7hjjq47px8m2prqk1gv4isy-hello-2.10
    lrwxrwxrwx 1 … result-1 -> /nix/store/frzgk3v1ycnarpfc2rkynravng27a86d-cowsay-3.03+dfsg2

•   Build GNU Hello and print the resulting store path.

    # nix build nixpkgs#hello --print-out-paths
    /nix/store/10l19qifk7hjjq47px8m2prqk1gv4isy-hello-2.10

•   Build a specific output:

    # nix build nixpkgs#glibc.dev
    # ls -ld ./result-dev
    lrwxrwxrwx 1 … ./result-dev -> /nix/store/hb4lb9n3gv855llky72hrs4pglpxq70m-glibc-2.32-dev

•   Build all outputs:

    # nix build "nixpkgs#openssl^*" --print-out-paths
    /nix/store/ah1slww3lfsj02w563wjf1xcz5fayj36-openssl-3.0.13-bin
    /nix/store/vswlynn75s0bpba3vl6bi3wyzjym95yi-openssl-3.0.13-debug
    /nix/store/z71nwwni9dcxdmd3v3a7j24v70c7v7z3-openssl-3.0.13-dev
    /nix/store/iabzsa5c73p4f10zfmf5r2qsrn0hl4lk-openssl-3.0.13-doc
    /nix/store/zqmfrpxvcll69a2lyawnpvp15zh421v2-openssl-3.0.13-man
    /nix/store/l3nlzki957anyy7yb25qvwk6cqrnvb67-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/frzgk3v1ycnarpfc2rkynravng27a86d-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). The input path must not be empty. 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.