nix-store-realise - Man Page

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

Each of paths is processed as follows:

• If the path leads to a store derivation :

  1. If it is not valid , substitute the store derivation file itself.
  2. Realise its output paths :

  • Try to fetch from substituters the store objects associated with the output paths in the store derivation's closure .

    • With content-addressing derivations\c : Determine the output paths to realise by querying content-addressed realisation entries in the Nix database .

  • 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 executable
• Otherwise, and if the path is not already valid: Try to fetch the associated store objects in the path's closure from substituters .

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}}

• --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}}

This operation is typically used to build store derivation s produced by nix-instantiate :

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

This is essentially what nix-build does.

To test whether a previously-built derivation is deterministic:

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

Use nix-store --read-log to show the stderr and stdout of a build:

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