the term was hard to discover, as its definition and explanation were in a very long document lacking an overview section. search did not help because it occurs so often. - clarify wording in the definition - add an overview of installable types - add "installable" to glossary - link to definition from occurrences of the term - be more precise about where store derivation outputs are processed - installable Nix expressions must evaluate to a derivation Co-authored-by: Adam Joseph <54836058+amjoseph-nixpkgs@users.noreply.github.com>
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R""(
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 aurls
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 byr:
ifhash
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 ofcurl
, and theout
output ofunzip
. -
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 thebash
shell (e.g./nix/store/r3j288vpmczbl500w6zz89gyfa4nr0b1-bash-4.4-p23/bin/bash
). -
args
: The command-line arguments passed to thebuilder
. -
env
: The environment passed to thebuilder
.
)""