Warning
This program is experimental and its interface is subject to change.

Name

nix derivation show - show the contents of a store derivation

Synopsis

nix derivation show [option...] installables...

Examples

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

    # nix derivation show nixpkgs#hello
    {
      "/nix/store/s6rn4jz1sin56rf4qj5b5v8jxjm32hlk-hello-2.10.drv": {
        …
      }
    }
    
  • Show the full derivation graph (if available) that produced your NixOS system:

    # nix derivation show -r /run/current-system
    
  • Print all files fetched using fetchurl by Firefox's dependency graph:

    # nix derivation show -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.

nix derivation show outputs a JSON map of store paths to derivations in the following format:

Derivation JSON Format

Warning

This JSON format is currently experimental and subject to change.

The JSON serialization of a derivations is a JSON object with the following fields:

  • name: The name of the derivation. This is used when calculating the store paths of the derivation's outputs.

  • 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, if it is known in advanced. Otherwise, null.

    • method: For an output which will be [content addresed], a string representing the method of content addressing that is chosen. Valid method strings are:

      Otherwise, null.

    • hashAlgo: For an output which will be [content addresed], the name of the hash algorithm used. Valid algorithm strings are:

      • md5
      • sha1
      • sha256
      • sha512
    • hash: For fixed-output derivations, the expected content hash in base-16.

    Example

    "outputs": {
      "out": {
        "path": "/nix/store/2543j7c6jn75blc3drf4g5vhb1rhdq29-source",
        "method": "nar",
        "hashAlgo": "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.

    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.

  • --stdin

    Read installables from the standard input. No default installable applied.

Common evaluation options

  • --arg name expr

    Pass the value expr as the argument name to Nix functions.

  • --arg-from-file name path

    Pass the contents of file path as the argument name to Nix functions.

  • --arg-from-stdin name

    Pass the contents of stdin as the argument name to Nix functions.

  • --argstr name string

    Pass the string string as the argument name to Nix functions.

  • --debugger

    Start an interactive environment if evaluation fails.

  • --eval-store store-url

    The URL of the Nix store to use for evaluation, i.e. to store derivations (.drv files) and inputs referenced by them.

  • --impure

    Allow access to mutable paths and repositories.

  • --include / -I path

    Add path to search path entries used to resolve lookup paths

    This option may be given multiple times.

    Paths added through -I take precedence over the nix-path configuration setting and the NIX_PATH environment variable.

  • --override-flake original-ref resolved-ref

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

  • --debug

    Set the logging verbosity level to 'debug'.

  • --log-format format

    Set the format of log output; one of raw, internal-json, bar or bar-with-logs.

  • --print-build-logs / -L

    Print full build logs on standard error.

  • --quiet

    Decrease the logging verbosity level.

  • --verbose / -v

    Increase the logging verbosity level.

Miscellaneous global options

  • --help

    Show usage information.

  • --offline

    Disable substituters and consider all previously downloaded files up-to-date.

  • --option name value

    Set the Nix configuration setting name to value (overriding nix.conf).

  • --refresh

    Consider all previously downloaded files out-of-date.

  • --repair

    During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.

  • --version

    Show version information.

Options that change the interpretation of installables

  • --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. Implies --impure.

Note

See man nix.conf for overriding configuration settings with command line flags.