Name

       nix-build - build a Nix expression

Synopsis

       nix-build  [paths…]  [--arg  name  value]  [--argstr name value] [{--attr | -A} attrPath] [--no-out-link]
       [--dry-run] [{--out-link | -o} outlink]

Disambiguation

       This man page describes the command nix-build, which is distinct from nix build. For documentation on the
       latter, run nix build --help or see man nix3-build.

Description

       The nix-build command builds the derivations described by the Nix expressions  in  paths.  If  the  build
       succeeds,  it  places  a symlink to the result in the current directory. The symlink is called result. If
       there are multiple Nix expressions, or the Nix expressions evaluate  to  multiple  derivations,  multiple
       sequentially numbered symlinks are created (result, result-2, and so on).

       If no paths are specified, then nix-build will use default.nix in the current directory, if it exists.

       If  an  element  of paths starts with http:// or https://, it is interpreted as the URL of a tarball that
       will be downloaded and unpacked to a temporary location. The tarball  must  include  a  single  top-level
       directory containing at least a file named default.nix.

       nix-build  is essentially a wrapper around nix-instantiate (to translate a high-level Nix expression to a
       low-level store derivation) and nix-store --realise (to build the store derivation).

              Warning

              The result of the build is automatically registered as a root of the Nix garbage  collector.  This
              root  disappears  automatically when the result symlink is deleted or renamed. So don’t rename the
              symlink.

Options

       All options not listed here are passed to nix-store --realise, except for --arg and --attr / -A which are
       passed to nix-instantiate.

       •  --no-out-link

          Do not create a symlink to the output path. Note that as a result the output does not become a root of
          the garbage collector, and so might be deleted by nix-store --gc.

       •  --dry-run

          Show what store paths would be built or downloaded.

       •  --out-link / -o outlink

          Change the name of the symlink to the output path created from result to outlink.

       {{#include ./status-build-failure.md}}

       {{#include ./opt-common.md}}

       {{#include ./env-common.md}}

Examples

       $ nix-build '<nixpkgs>' --attr firefox
       store derivation is /nix/store/qybprl8sz2lc...-firefox-1.5.0.7.drv
       /nix/store/d18hyl92g30l...-firefox-1.5.0.7

       $ ls -l result
       lrwxrwxrwx  ...  result -> /nix/store/d18hyl92g30l...-firefox-1.5.0.7

       $ ls ./result/bin/
       firefox  firefox-config

       If a derivation has multiple outputs, nix-build will build the default (first) output. You can also build
       all outputs:

       $ nix-build '<nixpkgs>' --attr openssl.all

       This will create a symlink for each output named result-outputname.  The suffix is omitted if the  output
       name  is  out. So if openssl has outputs out, bin and man, nix-build will create symlinks result, result-
       bin and result-man. It’s also possible to build a specific output:

       $ nix-build '<nixpkgs>' --attr openssl.man

       This will create a symlink result-man.

       Build a Nix expression given on the command line:

       $ nix-build --expr 'with import <nixpkgs> { }; runCommand "foo" { } "echo bar > $out"'
       $ cat ./result
       bar

       Build the GNU Hello package from the latest revision of the master branch of Nixpkgs:

       $ nix-build https://github.com/NixOS/nixpkgs/archive/master.tar.gz --attr hello

                                                                                                    nix-build(1)