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:

          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-addressed derivations: 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}}

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 derivations 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)

                                                                                          nix-store --realise(1)