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)