Usage

treefmt has the following specification:

Usage: treefmt [<paths> ...] [flags]

Arguments:
  [<paths> ...]    Paths to format. Defaults to formatting the whole tree.

Flags:
  -h, --help                            Show context-sensitive help.
      --allow-missing-formatter         Do not exit with error if a configured formatter is missing.
  -C, --working-directory="."           Run as if treefmt was started in the specified working directory instead of the current working directory.
      --no-cache                        Ignore the evaluation cache entirely. Useful for CI.
  -c, --clear-cache                     Reset the evaluation cache. Use in case the cache is not precise enough.
      --config-file="./treefmt.toml"    The config file to use.
      --fail-on-change                  Exit with error if any changes were made. Useful for CI.
      --formatters=FORMATTERS,...       Specify formatters to apply. Defaults to all formatters.
      --tree-root="."                   The root directory from which treefmt will start walking the filesystem.
      --walk="auto"                     The method used to traverse the files within --tree-root. Currently supports 'auto', 'git' or 'filesystem'.
  -v, --verbose                         Set the verbosity of logs e.g. -vv ($LOG_LEVEL).
  -V, --version                         Print version.
  -i, --init                            Create a new treefmt.toml.
  -u, --on-unmatched=warn               Log paths that did not match any formatters at the specified log level, with fatal exiting the process with an error. Possible values are <debug|info|warn|error|fatal>.
      --stdin                           Format the context passed in via stdin.
      --cpu-profile=STRING              The file into which a cpu profile will be written.

Arguments

[<paths> ...]

Paths to format. Defaults to formatting the whole tree

Flags

-h, --help

Prints available flags and options

--allow-missing-formatter

Do not exit with an error if some of the configured formatters are missing.

-C, --working-directory="."

Run as if treefmt was started in the specified working directory instead of the current working directory

--no-cache

Tells treefmt to ignore the evaluation cache entirely.

With this flag, you can avoid cache invalidation issues, if any. Typically, the machine that is running treefmt in CI is starting with a fresh environment each time, so any calculated cache is lost.

The --no-cache flag eliminates unnecessary work in CI.

--config-file <config-file>

Run with the specified config file.

--fail-on-change

Exit with error if any changes were made.

This is useful for CI if you want to detect if someone forgot to format their code.

-f, --formatters <formatters>...

Specify formatters to apply. Defaults to all formatters.

--tree-root="."

The root directory from which treefmt will start walking the filesystem.

--walk <auto|git|filesystem>

The method used to traverse the files within --tree-root. Currently supports auto, git or filesystem.

Default is auto, where we will detect if the <tree-root> is a git repository and use the git walker for traversal. If not we will fall back to the filesystem walker.

-v, --verbose

Set the verbosity of logs e.g. -vv. Can also be set with an integer value in an env variable $LOG_LEVEL.

Log verbosity is based off the number of 'v' used. With one -v, your logs will display [INFO] and [ERROR] messages, while -vv will also show [DEBUG] messages.

--init

Create a new treefmt.toml.

-u --on-unmatched

Log paths that did not match any formatters at the specified log level, with fatal exiting the process with an error. Possible values are <debug|info|warn|error|fatal>.

[default: warn]

--stdin

Format the context passed in via stdin.

--cpu-profile

The file into which a cpu profile will be written.

-V, --version

Print version.

CI integration

Typically, you would use treefmt in CI with the --fail-on-change and --no-cache flags.

You can configure a treefmt job in a GitHub pipeline for Ubuntu with nix-shell like this:

name: treefmt
on:
    pull_request:
    push:
        branches: main
jobs:
    formatter:
        runs-on: ubuntu-latest
        steps:
            - uses: actions/checkout@v4
            - uses: cachix/install-nix-action@v26
              with:
                  nix_path: nixpkgs=channel:nixos-unstable
            - uses: cachix/cachix-action@v14
              with:
                  name: nix-community
                  authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
            - name: treefmt
              run: nix-shell -p treefmt --run "treefmt --fail-on-change --no-cache"