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
-
Produce output in JSON format, suitable for consumption by another program.
Common evaluation options
-
--arg
name exprPass the value expr as the argument name to Nix functions.
-
--arg-from-file
name pathPass the contents of file path as the argument name to Nix functions.
-
--arg-from-stdin
namePass the contents of stdin as the argument name to Nix functions.
-
--argstr
name stringPass the string string as the argument name to Nix functions.
-
Start an interactive environment if evaluation fails.
-
--eval-store
store-urlThe URL of the Nix store to use for evaluation, i.e. to store derivations (
.drv
files) and inputs referenced by them. -
Allow access to mutable paths and repositories.
-
--include
/-I
pathAdd path to the Nix search path. The Nix search path is initialized from the colon-separated
NIX_PATH
environment variable, and is used to look up the location of Nix expressions using paths enclosed in angle brackets (i.e.,<nixpkgs>
).For instance, passing
-I /home/eelco/Dev -I /etc/nixos
will cause Nix to look for paths relative to
/home/eelco/Dev
and/etc/nixos
, in that order. This is equivalent to setting theNIX_PATH
environment variable to/home/eelco/Dev:/etc/nixos
It is also possible to match paths against a prefix. For example, passing
-I nixpkgs=/home/eelco/Dev/nixpkgs-branch -I /etc/nixos
will cause Nix to search for
<nixpkgs/path>
in/home/eelco/Dev/nixpkgs-branch/path
and/etc/nixos/nixpkgs/path
.If a path in the Nix search path starts with
http://
orhttps://
, it is interpreted as the URL of a tarball that will be downloaded and unpacked to a temporary location. The tarball must consist of a single top-level directory. For example, passing-I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz
tells Nix to download and use the current contents of the
master
branch in thenixpkgs
repository.The URLs of the tarballs from the official
nixos.org
channels (see the manual page fornix-channel
) can be abbreviated aschannel:<channel-name>
. For instance, the following two flags are equivalent:-I nixpkgs=channel:nixos-21.05 -I nixpkgs=https://nixos.org/channels/nixos-21.05/nixexprs.tar.xz
You can also fetch source trees using flake URLs and add them to the search path. For instance,
-I nixpkgs=flake:nixpkgs
specifies that the prefix
nixpkgs
shall refer to the source tree downloaded from thenixpkgs
entry in the flake registry. Similarly,-I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05
makes
<nixpkgs>
refer to a particular branch of theNixOS/nixpkgs
repository on GitHub. -
--override-flake
original-ref resolved-refOverride the flake registries, redirecting original-ref to resolved-ref.
Common flake-related options
-
Commit changes to the flake's lock file.
-
--inputs-from
flake-urlUse the inputs of the specified flake as registry entries.
-
Don't allow lookups in the flake registries.
DEPRECATED
Use
--no-use-registries
instead. -
Do not allow any updates to the flake's lock file.
-
Do not write the flake's newly generated lock file.
-
--output-lock-file
flake-lock-pathWrite the given lock file instead of
flake.lock
within the top-level flake. -
--override-input
input-path flake-urlOverride a specific flake input (e.g.
dwarffs/nixpkgs
). This implies--no-write-lock-file
. -
Recreate the flake's lock file from scratch.
DEPRECATED
Use
nix flake update
instead. -
--reference-lock-file
flake-lock-pathRead the given lock file instead of
flake.lock
within the top-level flake. -
--update-input
input-pathUpdate a specific flake input (ignoring its previous entry in the lock file).
DEPRECATED
Use
nix flake update
instead.
Logging-related options
-
Set the logging verbosity level to 'debug'.
-
--log-format
formatSet the format of log output; one of
raw
,internal-json
,bar
orbar-with-logs
. -
--print-build-logs
/-L
Print full build logs on standard error.
-
Decrease the logging verbosity level.
-
--verbose
/-v
Increase the logging verbosity level.
Miscellaneous global options
-
Show usage information.
-
Disable substituters and consider all previously downloaded files up-to-date.
-
--option
name valueSet the Nix configuration setting name to value (overriding
nix.conf
). -
Consider all previously downloaded files out-of-date.
-
During evaluation, rewrite missing or corrupted files in the Nix store. During building, rebuild missing or corrupted store paths.
-
Show version information.
Note
See
man nix.conf
for overriding configuration settings with command line flags.