Man page - nix3-flake-metadata(1)

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Manual

nix3-flake-metadata

Name
Synopsis
Examples
Description
Options
Common evaluation options
Common flake-related options
Logging-related options
Miscellaneous global options

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

Name

nix flake metadata - show flake metadata

Synopsis

nix flake metadata [ 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.