nix3-flake-prefetch(1)

    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 --out-link ./result
    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=').
    # cat ./result/README
    Linux kernel
    …

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

    # nix flake prefetch dwarffs --json
    {"hash":"sha256-VHg3MYVgQ12LeRSU2PSoDeKlSPD8PYYEFxxwkVVDRd0="
    ,"storePath":"/nix/store/l06r23gw4psl1f547il2hbnwnxaplbaz-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.

•   --no-pretty

    Print compact JSON output on a single line, even when the output is a terminal. Some commands may print multiple JSON objects on separate lines.

                See `--pretty`.

•   --out-link / -o path

    Create symlink named path to the resulting store path.

•   --pretty

    Print multi-line, indented JSON output for readability.

                Default: indent if output is to a terminal.
                This option is only effective when `--json` is also specified.

  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). The input path must not be empty. 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.