---
name: "nix-store-realise"
section: "1"
platform: "linux"
package: "nix-bin"
version: "2.26.3+dfsg-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/nix-store-realise"
---

# nix-store-realise(1)

build or fetch store objects

## Name

`nix-store --realise` - build or fetch store objects

## Synopsis

`nix-store` {`--realise` \| `-r`} *paths…* \[`--dry-run`\]

## Description

Each of *paths* is processed as follows:

- •

  If the path leads to a store derivation ⟨@docroot@/glossary.md#gloss-store-derivation⟩\\c :

  - 1\.

    If it is not valid ⟨@docroot@/glossary.md#gloss-validity⟩\\c , substitute the store derivation file itself.

  - 2\.

    Realise its output paths ⟨@docroot@/glossary.md#gloss-output-path⟩\\c :

  - •

    Try to fetch from substituters ⟨@docroot@/command-ref/conf-file.md#conf-substituters⟩ the store objects ⟨@docroot@/store/store-object.md⟩ associated with the output paths in the store derivation's closure ⟨@docroot@/glossary.md#gloss-closure⟩\\c .

    - •

      With content-addressed derivations ⟨experimental⟩\\c : Determine the output paths to realise by querying content-addressed realisation entries in the Nix database ⟨@docroot@/glossary.md#gloss-nix-database⟩\\c .

  - •

    For any store paths that cannot be substituted, produce the required store objects:

    - 1\.

      Realise all outputs of the derivation's dependencies

    - 2\.

      Run the derivation's `builder` ⟨@docroot@/language/derivations.md#attr-builder⟩ executable

- •

  Otherwise, and if the path is not already valid: Try to fetch the associated store objects ⟨@docroot@/store/store-object.md⟩ in the path's closure ⟨@docroot@/glossary.md#gloss-closure⟩ from substituters ⟨@docroot@/command-ref/conf-file.md#conf-substituters⟩\\c .

If no substitutes are available and no store derivation is given, realisation fails.

The resulting paths are printed on standard output. For non-derivation arguments, the argument itself is printed.

{{#include ../status-build-failure.md}}

## Options

- •

  `--dry-run`

-

  Print on standard error a description of what packages would be built or downloaded, without actually performing the operation.

- •

  `--ignore-unknown`

-

  If a non-derivation path does not have a substitute, then silently ignore it.

- •

  `--check`

-

  This option allows you to check whether a derivation is deterministic. It rebuilds the specified derivation and checks whether the result is bitwise-identical with the existing outputs, printing an error if that’s not the case. The outputs of the specified derivation must already exist. When used with `-K`, if an output path is not identical to the corresponding output from the previous build, the new output path is left in `/nix/store/name.check.`

{{#include ./opt-common.md}}

{{#include ../opt-common.md}}

{{#include ../env-common.md}}

## Examples

This operation is typically used to build store derivation ⟨@docroot@/glossary.md#gloss-store-derivation⟩\\c s produced by `nix-instantiate` ⟨@docroot@/command-ref/nix-instantiate.md⟩\\c :

```
$ nix-store --realise $(nix-instantiate ./test.nix)
/nix/store/31axcgrlbfsxzmfff1gyj1bf62hvkby2-aterm-2.3.1
```

This is essentially what `nix-build` ⟨@docroot@/command-ref/nix-build.md⟩ does.

To test whether a previously-built derivation is deterministic:

```
$ nix-build '<nixpkgs>' --attr hello --check -K
```

Use `nix-store --read-log` ⟨./read-log.md⟩ to show the stderr and stdout of a build:

```
$ nix-store --read-log $(nix-instantiate ./test.nix)
```