Name

       nix flake info - show flake metadata

Synopsis

       nix flake info [option…] flake-url

Examples

       •  Show what dwarffs resolves 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 dwarffs in 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 the description field in flake.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 for github flakes.

       •  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:

       •  original  and  originalUrl: The flake reference specified by the user (flake-url) in attribute set and
          URL representation.

       •  resolved and resolvedUrl:  The  resolved  flake  reference  (see  above)  in  attribute  set  and  URL
          representation.

       •  locked and lockedUrl: The locked flake reference (see above) in attribute set and URL representation.

       •  description: See Description above.

       •  path: See Path above.

       •  revision: See Revision above.

       •  revCount: See Revisions above.

       •  lastModified: See Last modified above.

       •  locks: The contents of flake.lock.

Options

       •  --json

          Produce output in JSON format, suitable for consumption by another program.

   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.

   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.

                 DEPRECATED

                 Use --no-use-registries instead.

       •  --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.

       •  --output-lock-file flake-lock-path

          Write the given lock file instead of flake.lock within the top-level flake.

       •  --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.

                 DEPRECATED

                 Use nix flake update instead.

       •  --reference-lock-file flake-lock-path

          Read the given lock file instead of flake.lock within the top-level flake.

       •  --update-input input-path

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

                 DEPRECATED

                 Use nix flake update instead.

   Logging-related options
       •  --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.

          Note

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

                                                                                              nix3-flake-info(1)