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 a specific output:

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

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

       # nix build -f 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.

       • --profile path
         The profile to update.

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

       Common evaluation options:

       • --arg name expr
         Pass the value expr as the argument name to Nix functions.

       • --argstr name string
         Pass the string string as the argument name to Nix functions.

       • --eval-store store-url
         The Nix store to use for evaluations.

       • --impure
         Allow access to mutable paths and repositories.

       • --include / -I path
         Add path to the list of locations used to look up <...> file names.

       • --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. This option is  deprecated;  use  --no-use-
         registries.

       • --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.

       • --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.

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

       Options that change the interpretation of installables:

       • --derivation
         Operate on the store derivation rather than its outputs.

       • --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.

                                                                                    nix3-build(1)