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.
• --argstr name string
  Pass the string string as the argument name to Nix functions.
• --eval-store store-url
  The Nix store to use for evaluations.
• --impure
  Allow access to mutable paths and repositories.
• --include / -I path
  Add path to the list of locations used to look up <...> file names.
• --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. This option is deprecated; use --no-use-registries.
• --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.
• --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.
• --update-input input-path
  Update a specific flake input (ignoring its previous entry in the lock file).