Name

       nix show-derivation - show the contents of a store derivation

Synopsis

       nix show-derivation [option…] installables…

Examples

       • Show the store derivation that results from evaluating the Hello package:

       # nix show-derivation nixpkgs#hello
       {
       "/nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv": {
         …
       }
       }

       • Show the full derivation graph (if available) that produced your NixOS system:

       # nix show-derivation -r /run/current-system

       • Print all files fetched using fetchurl by Firefox’s dependency graph:

       # nix show-derivation -r nixpkgs#firefox \
       | jq -r '.[] | select(.outputs.out.hash and .env.urls) | .env.urls' \
       | uniq | sort

              Note  that  .outputs.out.hash  selects  fixed-output  derivations (derivations that
              produce output with a specified content hash), while .env.urls selects  derivations
              with a urls attribute.

Description

       This  command  prints on standard output a JSON representation of the store derivations to
       which installables evaluate. Store derivations are used internally by Nix. They are  store
       paths  with  extension  .drv that represent the build-time dependency graph to which a Nix
       expression evaluates.

       By default, this command only shows top-level derivations, but with --recursive,  it  also
       shows their dependencies.

       The  JSON  output  is a JSON object whose keys are the store paths of the derivations, and
       whose values are a JSON object with the following fields:

       • outputs: Information about the output paths of the derivation. This  is  a  JSON  object
         with  one  member  per  output, where the key is the output name and the value is a JSON
         object with these fields:

         • path: The output path.
         • hashAlgo:  For  fixed-output  derivations,  the  hashing  algorithm   (e.g.   sha256),
           optionally prefixed by r: if hash denotes a NAR hash rather than a flat file hash.
         • hash: For fixed-output derivations, the expected content hash in base-16.

         Example:

       "outputs": {
       "out": {
         "path": "/nix/store/2543j7c6jn75blc3drf4g5vhb1rhdq29-source",
         "hashAlgo": "r:sha256",
         "hash": "6fc80dcc62179dbc12fc0b5881275898f93444833d21b89dfe5f7fbcbb1d0d62"
       }
       }

       • inputSrcs: A list of store paths on which this derivation depends.

       • inputDrvs:  A  JSON  object specifying the derivations on which this derivation depends,
         and what outputs of those derivations. For example,

       "inputDrvs": {
       "/nix/store/6lkh5yi7nlb7l6dr8fljlli5zfd9hq58-curl-7.73.0.drv": ["dev"],
       "/nix/store/fn3kgnfzl5dzym26j8g907gq3kbm8bfh-unzip-6.0.drv": ["out"]
       }

              specifies that this derivation depends on the dev  output  of  curl,  and  the  out
              output of unzip.

       • system: The system type on which this derivation is to be built (e.g. x86_64-linux).

       • builder:  The  absolute  path  of the program to be executed to run the build. Typically
         this             is             the             bash             shell             (e.g.
         /nix/store/r3j288vpmczbl500w6zz89gyfa4nr0b1-bash-4.4-p23/bin/bash).

       • args: The command-line arguments passed to the builder.

       • env: The environment passed to the builder.

Options

       • --recursive / -r
         Include the dependencies of the specified derivations.

       Common evaluation options:

       • --arg name expr
         Pass the value expr as the argument name to Nix functions.

       • --argstr name string
         Pass the string string as the argument name to Nix functions.

       • --eval-store store-url
         The Nix store to use for evaluations.

       • --impure
         Allow access to mutable paths and repositories.

       • --include / -I path
         Add path to the list of locations used to look up <...> file names.

       • --override-flake original-ref resolved-ref
         Override the flake registries, redirecting original-ref to resolved-ref.

       Common flake-related options:

       • --commit-lock-file
         Commit changes to the flake’s lock file.

       • --inputs-from flake-url
         Use the inputs of the specified flake as registry entries.

       • --no-registries
         Don’t  allow  lookups  in the flake registries. This option is deprecated; use --no-use-
         registries.

       • --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.

       • --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.

       • --update-input input-path
         Update a specific flake input (ignoring its previous entry in the lock file).

       Options that change the interpretation of installables:

       • --derivation
         Operate on the store derivation rather than its outputs.

       • --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.

                                                                          nix3-show-derivation(1)