nix3-build(1) General Commands Manual nix3-build(1)

Warning
This program is experimental and its interface is subject to change.

nix build - build a derivation or fetch a store path

nix build [option…] installables…

•
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
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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-linux from (non-flake) Nix expression release.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-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

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).

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--dry-run
Show what this command would do without doing it.
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--json
Produce output in JSON format, suitable for consumption by another program.
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--no-link
Do not create symlinks to the build results.
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--out-link / -o path
Use path as prefix for the symlinks to the build results. It defaults to result.
•
--print-out-paths
Print the resulting output paths
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--profile path
The profile to operate on.
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--rebuild
Rebuild an already built package and compare the result to the existing store paths.
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--stdin
Read installables from the standard input. No default installable applied.

•
--arg name expr
Pass the value expr as the argument name to Nix functions.
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--arg-from-file name path
Pass the contents of file path as the argument name to Nix functions.
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--arg-from-stdin name
Pass the contents of stdin as the argument name to Nix functions.
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--argstr name string
Pass the string string as the argument name to Nix functions.
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--debugger
Start an interactive environment if evaluation fails.
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--eval-store store-url
The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.
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--impure
Allow access to mutable paths and repositories.
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--include / -I path
Add path to search path entries used to resolve lookup paths
This option may be given multiple times.
Paths added through -I take precedence over the nix-path configuration setting and the NIX_PATH environment variable.
•
--override-flake original-ref resolved-ref
Override the flake registries, redirecting original-ref to resolved-ref.
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--commit-lock-file
Commit changes to the flake’s lock file.
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--inputs-from flake-url
Use the inputs of the specified flake as registry entries.
•
--no-registries
Don’t allow lookups in the flake registries.
DEPRECATED
Use --no-use-registries instead.
•
--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.
•
--output-lock-file flake-lock-path
Write the given lock file instead of flake.lock within the top-level flake.
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--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.
DEPRECATED
Use nix flake update instead.
•
--reference-lock-file flake-lock-path
Read the given lock file instead of flake.lock within the top-level flake.
•
--update-input input-path
Update a specific flake input (ignoring its previous entry in the lock file).
DEPRECATED
Use nix flake update instead.
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--debug
Set the logging verbosity level to ‘debug’.
•
--log-format format
Set the format of log output; one of raw, internal-json, bar or bar-with-logs.
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--print-build-logs / -L
Print full build logs on standard error.
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--quiet
Decrease the logging verbosity level.
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--verbose / -v
Increase the logging verbosity level.

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--help
Show usage information.
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--offline
Disable substituters and consider all previously downloaded files up-to-date.
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--option name value
Set the Nix configuration setting name to value (overriding nix.conf).
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--refresh
Consider all previously downloaded files out-of-date.
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--repair
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
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--version
Show version information.

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--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. Implies --impure.

Note

See man nix.conf for overriding configuration settings with command line flags.