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

Name

nix flake prefetch - download the source tree denoted by a flake reference into the Nix store

Synopsis

nix flake prefetch [option...] flake-url

Examples

Download a tarball and unpack it:

# nix flake prefetch https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.5.tar.xz
Downloaded 'https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.5.tar.xz?narHash=sha256-3XYHZANT6AFBV0BqegkAZHbba6oeDkIUCDwbATLMhAY='
to '/nix/store/sl5vvk8mb4ma1sjyy03kwpvkz50hd22d-source' (hash
'sha256-3XYHZANT6AFBV0BqegkAZHbba6oeDkIUCDwbATLMhAY=').

Download the dwarffs flake (looked up in the flake registry):

# nix flake prefetch dwarffs --json
{"hash":"sha256-VHg3MYVgQ12LeRSU2PSoDeKlSPD8PYYEFxxwkVVDRd0="
,"storePath":"/nix/store/hang3792qwdmm2n0d9nsrs5n6bsws6kv-source"}

Description

This command downloads the source tree denoted by flake reference flake-url. Note that this does not need to be a flake (i.e. it does not have to contain a flake.nix file).

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.

--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.

--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.

Nix Reference Manual