.\" -*- mode: troff; coding: utf-8 -*-
.TH "nix3-flake-info" "1" ""
.PP
\fBWarning\fR: This program is \fBexperimental\fR and its interface is subject to change.
.SH Name
\fCnix flake info\fR - show flake metadata
.SH Synopsis
\fCnix flake info\fR [\fIoption\fR\[u2026]] \fIflake-url\fR
.SH Examples
.IP "\(bu" 2
Show what \fCnixpkgs\fR resolves to:
.LP
.EX
# nix flake metadata nixpkgs
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'
.EE
.IP "\(bu" 2
Show information about \fCdwarffs\fR in JSON format:
.LP
.EX
# nix flake metadata dwarffs --json | jq .
{
\(dqdescription\(dq: \(dqA filesystem that fetches DWARF debug info from the Internet on demand\(dq,
\(dqlastModified\(dq: 1597153508,
\(dqlocked\(dq: {
  \(dqlastModified\(dq: 1597153508,
  \(dqnarHash\(dq: \(dqsha256-VHg3MYVgQ12LeRSU2PSoDeKlSPD8PYYEFxxwkVVDRd0=\(dq,
  \(dqowner\(dq: \(dqedolstra\(dq,
  \(dqrepo\(dq: \(dqdwarffs\(dq,
  \(dqrev\(dq: \(dqd181d714fd36eb06f4992a1997cd5601e26db8f5\(dq,
  \(dqtype\(dq: \(dqgithub\(dq
},
\(dqlocks\(dq: { ... },
\(dqoriginal\(dq: {
  \(dqid\(dq: \(dqdwarffs\(dq,
  \(dqtype\(dq: \(dqindirect\(dq
},
\(dqoriginalUrl\(dq: \(dqflake:dwarffs\(dq,
\(dqpath\(dq: \(dq/nix/store/hang3792qwdmm2n0d9nsrs5n6bsws6kv-source\(dq,
\(dqresolved\(dq: {
  \(dqowner\(dq: \(dqedolstra\(dq,
  \(dqrepo\(dq: \(dqdwarffs\(dq,
  \(dqtype\(dq: \(dqgithub\(dq
},
\(dqresolvedUrl\(dq: \(dqgithub:edolstra/dwarffs\(dq,
\(dqrevision\(dq: \(dqd181d714fd36eb06f4992a1997cd5601e26db8f5\(dq,
\(dqurl\(dq: \(dqgithub:edolstra/dwarffs/d181d714fd36eb06f4992a1997cd5601e26db8f5\(dq
}
.EE
.SH Description
This command shows information about the flake specified by the flake
reference \fIflake-url\fR. It resolves the flake reference using the
\fBflake registry\fR (\fI./nix3-registry.md\fR), fetches it, and prints some meta
data. This includes:
.IP "\(bu" 2
\fCResolved URL\fR: If \fIflake-url\fR is a flake identifier, then this is
the flake reference that specifies its actual location, looked up in
the flake registry.
.IP "\(bu" 2
\fCLocked URL\fR: A flake reference that contains a commit or content
hash and thus uniquely identifies a specific flake version.
.IP "\(bu" 2
\fCDescription\fR: A one-line description of the flake, taken from the
\fCdescription\fR field in \fCflake.nix\fR.
.IP "\(bu" 2
\fCPath\fR: The store path containing the source code of the flake.
.IP "\(bu" 2
\fCRevision\fR: The Git or Mercurial commit hash of the locked flake.
.IP "\(bu" 2
\fCRevisions\fR: The number of ancestors of the Git or Mercurial commit
of the locked flake. Note that this is not available for \fCgithub\fR
flakes.
.IP "\(bu" 2
\fCLast modified\fR: For Git or Mercurial flakes, this is the commit
time of the commit of the locked flake; for tarball flakes, it\[u2019]s the
most recent timestamp of any file inside the tarball.
.IP "\(bu" 2
\fCInputs\fR: The flake inputs with their corresponding lock file
entries.
.LP
With \fC--json\fR, the output is a JSON object with the following fields:
.IP "\(bu" 2
\fCoriginal\fR and \fCoriginalUrl\fR: The flake reference specified by the
user (\fIflake-url\fR) in attribute set and URL representation.
.IP "\(bu" 2
\fCresolved\fR and \fCresolvedUrl\fR: The resolved flake reference (see
above) in attribute set and URL representation.
.IP "\(bu" 2
\fClocked\fR and \fClockedUrl\fR: The locked flake reference (see above) in
attribute set and URL representation.
.IP "\(bu" 2
\fCdescription\fR: See \fCDescription\fR above.
.IP "\(bu" 2
\fCpath\fR: See \fCPath\fR above.
.IP "\(bu" 2
\fCrevision\fR: See \fCRevision\fR above.
.IP "\(bu" 2
\fCrevCount\fR: See \fCRevisions\fR above.
.IP "\(bu" 2
\fClastModified\fR: See \fCLast modified\fR above.
.IP "\(bu" 2
\fClocks\fR: The contents of \fCflake.lock\fR.
.SH Options
.IP "\(bu" 2
\fC--json\fR
.br
Produce output in JSON format, suitable for consumption by another program.
.LP
\fBCommon evaluation options:\fR
.IP "\(bu" 2
\fC--arg\fR \fIname\fR \fIexpr\fR
.br
Pass the value \fIexpr\fR as the argument \fIname\fR to Nix functions.
.IP "\(bu" 2
\fC--argstr\fR \fIname\fR \fIstring\fR
.br
Pass the string \fIstring\fR as the argument \fIname\fR to Nix functions.
.IP "\(bu" 2
\fC--eval-store\fR \fIstore-url\fR
.br
The Nix store to use for evaluations.
.IP "\(bu" 2
\fC--impure\fR
.br
Allow access to mutable paths and repositories.
.IP "\(bu" 2
\fC--include\fR / \fC-I\fR \fIpath\fR
.br
Add \fIpath\fR to the list of locations used to look up \fC<...>\fR file names.
.IP "\(bu" 2
\fC--override-flake\fR \fIoriginal-ref\fR \fIresolved-ref\fR
.br
Override the flake registries, redirecting \fIoriginal-ref\fR to \fIresolved-ref\fR.
.LP
\fBCommon flake-related options:\fR
.IP "\(bu" 2
\fC--commit-lock-file\fR
.br
Commit changes to the flake\[u2019]s lock file.
.IP "\(bu" 2
\fC--inputs-from\fR \fIflake-url\fR
.br
Use the inputs of the specified flake as registry entries.
.IP "\(bu" 2
\fC--no-registries\fR
.br
Don\[u2019]t allow lookups in the flake registries. This option is deprecated; use \fC--no-use-registries\fR.
.IP "\(bu" 2
\fC--no-update-lock-file\fR
.br
Do not allow any updates to the flake\[u2019]s lock file.
.IP "\(bu" 2
\fC--no-write-lock-file\fR
.br
Do not write the flake\[u2019]s newly generated lock file.
.IP "\(bu" 2
\fC--override-input\fR \fIinput-path\fR \fIflake-url\fR
.br
Override a specific flake input (e.g. \fCdwarffs/nixpkgs\fR). This implies \fC--no-write-lock-file\fR.
.IP "\(bu" 2
\fC--recreate-lock-file\fR
.br
Recreate the flake\[u2019]s lock file from scratch.
.IP "\(bu" 2
\fC--update-input\fR \fIinput-path\fR
.br
Update a specific flake input (ignoring its previous entry in the lock file).