table of contents
nix3-fmt(1) | General Commands Manual | nix3-fmt(1) |
Warning: This program is experimental and its interface is subject to change.
Name¶
nix fmt - reformat your code in the standard style
Synopsis¶
nix fmt [option…] args…
Examples¶
With nixpkgs-fmt (https://github.com/nix-community/nixpkgs-fmt):
# flake.nix {
outputs = { nixpkgs, self }: {
formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixpkgs-fmt;
}; }
- Format the current flake: $ nix fmt
- Format a specific folder or file: $ nix fmt ./folder ./file.nix
With nixfmt (https://github.com/serokell/nixfmt):
# flake.nix {
outputs = { nixpkgs, self }: {
formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt;
}; }
- •
- Format specific files: $ nix fmt ./file1.nix ./file2.nix
With Alejandra (https://github.com/kamadorueda/alejandra):
# flake.nix {
outputs = { nixpkgs, self }: {
formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.alejandra;
}; }
- Format the current flake: $ nix fmt
- Format a specific folder or file: $ nix fmt ./folder ./file.nix
Description¶
nix fmt will rewrite all Nix files (*.nix) to a canonical format using the formatter specified in your flake.
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. - --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).
Options that change the interpretation of installables:
- --derivation
Operate on the store derivation rather than its outputs. - --expr expr
Interpret installables as attribute paths relative to the Nix expression expr. - --file / -f file
Interpret installables as attribute paths relative to the Nix expression stored in file. If file is the character -, then a Nix expression will be read from standard input.