Warning
This program is experimental and its interface is subject to change.
Name
nix flake info - show flake metadata
Synopsis
nix flake info [option...] flake-url
Examples
- 
Show what dwarffsresolves to:# nix flake metadata dwarffs Resolved URL: github:edolstra/dwarffs Locked URL: github:edolstra/dwarffs/f691e2c991e75edb22836f1dbe632c40324215c5 Description: A filesystem that fetches DWARF debug info from the Internet on demand Path: /nix/store/769s05vjydmc2lcf6b02az28wsa9ixh1-source Revision: f691e2c991e75edb22836f1dbe632c40324215c5 Last modified: 2021-01-21 15:41:26 Inputs: ├───nix: github:NixOS/nix/6254b1f5d298ff73127d7b0f0da48f142bdc753c │ ├───lowdown-src: github:kristapsdz/lowdown/1705b4a26fbf065d9574dce47a94e8c7c79e052f │ └───nixpkgs: github:NixOS/nixpkgs/ad0d20345219790533ebe06571f82ed6b034db31 └───nixpkgs follows input 'nix/nixpkgs'
- 
Show information about dwarffsin JSON format:# nix flake metadata dwarffs --json | jq . { "description": "A filesystem that fetches DWARF debug info from the Internet on demand", "lastModified": 1597153508, "locked": { "lastModified": 1597153508, "narHash": "sha256-VHg3MYVgQ12LeRSU2PSoDeKlSPD8PYYEFxxwkVVDRd0=", "owner": "edolstra", "repo": "dwarffs", "rev": "d181d714fd36eb06f4992a1997cd5601e26db8f5", "type": "github" }, "locks": { ... }, "original": { "id": "dwarffs", "type": "indirect" }, "originalUrl": "flake:dwarffs", "path": "/nix/store/hang3792qwdmm2n0d9nsrs5n6bsws6kv-source", "resolved": { "owner": "edolstra", "repo": "dwarffs", "type": "github" }, "resolvedUrl": "github:edolstra/dwarffs", "revision": "d181d714fd36eb06f4992a1997cd5601e26db8f5", "url": "github:edolstra/dwarffs/d181d714fd36eb06f4992a1997cd5601e26db8f5" }
Description
This command shows information about the flake specified by the flake reference flake-url. It resolves the flake reference using the flake registry, fetches it, and prints some meta data. This includes:
- 
Resolved URL: If flake-url is a flake identifier, then this is the flake reference that specifies its actual location, looked up in the flake registry.
- 
Locked URL: A flake reference that contains a commit or content hash and thus uniquely identifies a specific flake version.
- 
Description: A one-line description of the flake, taken from thedescriptionfield inflake.nix.
- 
Path: The store path containing the source code of the flake.
- 
Revision: The Git or Mercurial commit hash of the locked flake.
- 
Revisions: The number of ancestors of the Git or Mercurial commit of the locked flake. Note that this is not available forgithubflakes.
- 
Last modified: For Git or Mercurial flakes, this is the commit time of the commit of the locked flake; for tarball flakes, it's the most recent timestamp of any file inside the tarball.
- 
Inputs: The flake inputs with their corresponding lock file entries.
With --json, the output is a JSON object with the following fields:
- 
originalandoriginalUrl: The flake reference specified by the user (flake-url) in attribute set and URL representation.
- 
resolvedandresolvedUrl: The resolved flake reference (see above) in attribute set and URL representation.
- 
lockedandlockedUrl: The locked flake reference (see above) in attribute set and URL representation.
- 
description: SeeDescriptionabove.
- 
path: SeePathabove.
- 
revision: SeeRevisionabove.
- 
revCount: SeeRevisionsabove.
- 
lastModified: SeeLast modifiedabove.
- 
locks: The contents offlake.lock.
Options
- 
Produce output in JSON format, suitable for consumption by another program. 
Common evaluation options
- 
--argname exprPass the value expr as the argument name to Nix functions. 
- 
--arg-from-filename pathPass the contents of file path as the argument name to Nix functions. 
- 
--arg-from-stdinnamePass the contents of stdin as the argument name to Nix functions. 
- 
--argstrname stringPass the string string as the argument name to Nix functions. 
- 
Start an interactive environment if evaluation fails. 
- 
--eval-storestore-urlThe URL of the Nix store to use for evaluation, i.e. to store derivations ( .drvfiles) and inputs referenced by them.
- 
Allow access to mutable paths and repositories. 
- 
--include/-IpathAdd path to search path entries used to resolve lookup paths This option may be given multiple times. Paths added through -Itake precedence over thenix-pathconfiguration setting and theNIX_PATHenvironment variable.
- 
--override-flakeoriginal-ref resolved-refOverride the flake registries, redirecting original-ref to resolved-ref. 
Common flake-related options
- 
Commit changes to the flake's lock file. 
- 
--inputs-fromflake-urlUse the inputs of the specified flake as registry entries. 
- 
Don't allow lookups in the flake registries. DEPRECATED Use --no-use-registriesinstead.
- 
Do not allow any updates to the flake's lock file. 
- 
Do not write the flake's newly generated lock file. 
- 
--output-lock-fileflake-lock-pathWrite the given lock file instead of flake.lockwithin the top-level flake.
- 
--override-inputinput-path flake-urlOverride a specific flake input (e.g. dwarffs/nixpkgs). This implies--no-write-lock-file.
- 
Recreate the flake's lock file from scratch. DEPRECATED Use nix flake updateinstead.
- 
--reference-lock-fileflake-lock-pathRead the given lock file instead of flake.lockwithin the top-level flake.
- 
--update-inputinput-pathUpdate a specific flake input (ignoring its previous entry in the lock file). DEPRECATED Use nix flake updateinstead.
Logging-related options
- 
Set the logging verbosity level to 'debug'. 
- 
--log-formatformatSet the format of log output; one of raw,internal-json,barorbar-with-logs.
- 
--print-build-logs/-LPrint full build logs on standard error. 
- 
Decrease the logging verbosity level. 
- 
--verbose/-vIncrease the logging verbosity level. 
Miscellaneous global options
- 
Show usage information. 
- 
Disable substituters and consider all previously downloaded files up-to-date. 
- 
--optionname valueSet the Nix configuration setting name to value (overriding nix.conf).
- 
Consider all previously downloaded files out-of-date. 
- 
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths. 
- 
Show version information. 
Note
See
man nix.conffor overriding configuration settings with command line flags.