R""(

Note: this command's interface is based heavily around installables, which you may want to read about first (nix --help).

Examples

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

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 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
```

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).

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