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
nixpkgsflake:# 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 GNU Hello and print the resulting store path.
# nix build nixpkgs#hello --print-out-paths /nix/store/v5sv61sszx301i0x6xysaqzla09nksnd-hello-2.10 -
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 all outputs:
# nix build "nixpkgs#openssl^*" --print-out-paths /nix/store/gvad6v0cmq1qccmc4wphsazqbj0xzjsl-openssl-3.0.13-bin /nix/store/a07jqdrc8afnk8r6f3lnhh4gvab7chk4-openssl-3.0.13-debug /nix/store/yg75achq89wgqn2fi3gglgsd77kjpi03-openssl-3.0.13-dev /nix/store/bvdcihi8c88fw31cg6gzzmpnwglpn1jv-openssl-3.0.13-doc /nix/store/gjqcvq47cmxazxga0cirspm3jywkmvfv-openssl-3.0.13-man /nix/store/7nmrrad8skxr47f9hfl3xc0pfqmwq51b-openssl-3.0.13 -
Build attribute
build.x86_64-linuxfrom (non-flake) Nix expressionrelease.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-rebuilddoes.) -
Build an expression specified on the command line:
# nix build --impure --expr \ 'with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ hello ]; } "hello > $out"' # cat ./result Hello, world!Note that
--impureis needed because we're using<nixpkgs>, which relies on the$NIX_PATHenvironment 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
-
Show what this command would do without doing it.
-
Produce output in JSON format, suitable for consumption by another program.
-
Do not create symlinks to the build results.
-
--out-link/-opathUse path as prefix for the symlinks to the build results. It defaults to
result. -
Print the resulting output paths
-
--profilepathThe profile to operate on.
-
Rebuild an already built package and compare the result to the existing store paths.
-
Read installables from the standard input. No default installable applied.
Common evaluation options
-
--argname exprPass the value expr as the argument name to Nix functions.
-
--arg-from-filename pathPass the contents of file path as the argument name to Nix functions.
-
--arg-from-stdinnamePass the contents of stdin as the argument name to Nix functions.
-
--argstrname stringPass the string string as the argument name to Nix functions.
-
Start an interactive environment if evaluation fails.
-
--eval-storestore-urlThe URL of the Nix store to use for evaluation, i.e. to store derivations (
.drvfiles) and inputs referenced by them. -
Allow access to mutable paths and repositories.
-
--include/-IpathAdd path to the Nix search path. The Nix search path is initialized from the colon-separated
NIX_PATHenvironment variable, and is used to look up the location of Nix expressions using paths enclosed in angle brackets (i.e.,<nixpkgs>).For instance, passing
-I /home/eelco/Dev -I /etc/nixoswill cause Nix to look for paths relative to
/home/eelco/Devand/etc/nixos, in that order. This is equivalent to setting theNIX_PATHenvironment variable to/home/eelco/Dev:/etc/nixosIt is also possible to match paths against a prefix. For example, passing
-I nixpkgs=/home/eelco/Dev/nixpkgs-branch -I /etc/nixoswill cause Nix to search for
<nixpkgs/path>in/home/eelco/Dev/nixpkgs-branch/pathand/etc/nixos/nixpkgs/path.If a path in the Nix search path starts with
http://orhttps://, it is interpreted as the URL of a tarball that will be downloaded and unpacked to a temporary location. The tarball must consist of a single top-level directory. For example, passing-I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gztells Nix to download and use the current contents of the
masterbranch in thenixpkgsrepository.The URLs of the tarballs from the official
nixos.orgchannels (see the manual page fornix-channel) can be abbreviated aschannel:<channel-name>. For instance, the following two flags are equivalent:-I nixpkgs=channel:nixos-21.05 -I nixpkgs=https://nixos.org/channels/nixos-21.05/nixexprs.tar.xzYou can also fetch source trees using flake URLs and add them to the search path. For instance,
-I nixpkgs=flake:nixpkgsspecifies that the prefix
nixpkgsshall refer to the source tree downloaded from thenixpkgsentry in the flake registry. Similarly,-I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05makes
<nixpkgs>refer to a particular branch of theNixOS/nixpkgsrepository on GitHub. -
--override-flakeoriginal-ref resolved-refOverride the flake registries, redirecting original-ref to resolved-ref.
Common flake-related options
-
Commit changes to the flake's lock file.
-
--inputs-fromflake-urlUse the inputs of the specified flake as registry entries.
-
Don't allow lookups in the flake registries.
DEPRECATED
Use
--no-use-registriesinstead. -
Do not allow any updates to the flake's lock file.
-
Do not write the flake's newly generated lock file.
-
--output-lock-fileflake-lock-pathWrite the given lock file instead of
flake.lockwithin the top-level flake. -
--override-inputinput-path flake-urlOverride a specific flake input (e.g.
dwarffs/nixpkgs). This implies--no-write-lock-file. -
Recreate the flake's lock file from scratch.
DEPRECATED
Use
nix flake updateinstead. -
--reference-lock-fileflake-lock-pathRead the given lock file instead of
flake.lockwithin the top-level flake. -
--update-inputinput-pathUpdate a specific flake input (ignoring its previous entry in the lock file).
DEPRECATED
Use
nix flake updateinstead.
Logging-related options
-
Set the logging verbosity level to 'debug'.
-
--log-formatformatSet the format of log output; one of
raw,internal-json,barorbar-with-logs. -
--print-build-logs/-LPrint full build logs on standard error.
-
Decrease the logging verbosity level.
-
--verbose/-vIncrease the logging verbosity level.
Miscellaneous global options
-
Show usage information.
-
Disable substituters and consider all previously downloaded files up-to-date.
-
--optionname valueSet the Nix configuration setting name to value (overriding
nix.conf). -
Consider all previously downloaded files out-of-date.
-
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
-
Show version information.
Options that change the interpretation of installables
-
--exprexprInterpret installables as attribute paths relative to the Nix expression expr.
-
--file/-ffileInterpret 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. Implies
--impure.
Note
See
man nix.conffor overriding configuration settings with command line flags.