nixfmt is a formatter for Nix code, intended to easily apply a uniform style.

You are encouraged to test this out on your code and submit any undesirable formatting you find as an issue

nixfmt will form the basis for the initial official standard Nix formatter, as established by RFC 166.

The established standard Nix formatting differs considerably from the original one. Be aware of this if you track the main branch. Until the first new release the main branch should be considered very unstable.

For more details, see the RFC implementation tracking issue.

• nixfmt is in nixpkgs master as of 2019-09-04:

  nix-env -iA nixpkgs.nixfmt
  

• To get the most recent version, install from master:

  nix-env -f https://github.com/NixOS/nixfmt/archive/master.tar.gz -i
  

• Nix with flakes

  nix profile install github:NixOS/nixfmt
  

Haskell dependencies will be built by Nix.

• Enter nix-shell
• Build with cabal new-build

Haskell dependencies will be built by Cabal.

• Build with cabal new-build

• nixfmt < input.nix – reads Nix code from stdin, formats it, and outputs to stdout
• nixfmt file.nix – format the file in place

nixfmt is maintained and funded with ❤️ by Serokell. The names and logo for Serokell are trademark of Serokell OÜ.

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