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]

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 (nix-instantiate.md) (to translate a high-level
       Nix    expression    to    a    low-level    store    derivation)    and    nix-store   --realise   (nix-
       store.md#operation---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.

       The following common options are supported:

Examples

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

       This will create a symlink result-man.

       Build a Nix expression given on the command line:

       $ nix-build -E '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 -A hello

                                                                                                    nix-build(1)