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nix flake lock

Create missing lock file entries.

Warning

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

Synopsis

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

Examples

  • Create the lock file for the flake in the current directory:
## nix flake lock
warning: creating lock file '/home/myself/repos/testflake/flake.lock':
• Added input 'nix':
    'github:NixOS/nix/9fab14adbc3810d5cc1f88672fde1eee4358405c' (2023-06-28)
• Added input 'nixpkgs':
    'github:NixOS/nixpkgs/3d2d8f281a27d466fa54b469b5993f7dde198375' (2023-06-30)
  • Add missing inputs to the lock file for a flake in a different directory:
## nix flake lock ~/repos/another
warning: updating lock file '/home/myself/repos/another/flake.lock':
• Added input 'nixpkgs':
    'github:NixOS/nixpkgs/3d2d8f281a27d466fa54b469b5993f7dde198375' (2023-06-30)

Note

When trying to refer to a flake in a subdirectory, write ./another instead of another. Otherwise Lix will try to look up the flake in the registry.

Description

This command adds inputs to the lock file of a flake (flake.lock) so that it contains a lock for every flake input specified in flake.nix. Existing lock file entries are not updated.

If you want to update existing lock entries, use nix flake update

Options

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.

  • --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 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 Lix to look for paths relative to /home/eelco/Dev and /etc/nixos, in that order. This is equivalent to setting the NIX_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 Lix 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:// or https://, 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 Lix to download and use the current contents of the master branch in the nixpkgs repository.

The URLs of the tarballs from the official nixos.org channels (see the manual page for nix-channel) can be abbreviated as channel:<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 the nixpkgs entry in the flake registry. Similarly,

-I nixpkgs=flake:github:NixOS/nixpkgs/nixos-22.05

makes <nixpkgs> refer to a particular branch of the NixOS/nixpkgs repository on GitHub.

  • --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.

  • --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.

  • --reference-lock-file flake-lock-path Read the given lock file instead of flake.lock within the top-level flake.

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 Lix 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.