rustfmt

Format a Rust file

$ rustfmt [main.rs]

$ rustfmt [src/*.rs]

$ rustfmt --check [main.rs]

$ rustfmt --backup [main.rs]

$ rustfmt --edition [2021] [main.rs]

$ cat [main.rs] | rustfmt

$ rustfmt --emit files --check [main.rs]

$ rustfmt --config-path [rustfmt.toml] [main.rs]

rustfmt [options] [files...]

rustfmt is the official Rust code formatter. It automatically formats Rust code according to style guidelines, ensuring consistent code style across a project.
The tool can be integrated into editors, CI pipelines, and pre-commit hooks. Configuration is stored in rustfmt.toml or .rustfmt.toml at the project root.
When used with Cargo (`cargo fmt`), it formats all files in the project automatically. rustfmt supports all stable Rust syntax and can be configured for various style preferences.

--check

Check if formatting is correct, don't modify.

Create backup of original files.

Rust edition (2015, 2018, 2021).

Output mode (files, stdout, checkstyle).

Set configuration option.

Path to configuration file.

Print configuration (default, current, minimal).

Print files that would change.

Print verbose output.

Print minimal output.

Color output (auto, always, never).

rustfmt.toml / .rustfmt.toml

Project-level configuration file at the project root defining formatting rules such as maxwidth, tabspaces, edition, and usesmallheuristics.

Maximum line width before wrapping (default 100).

Number of spaces per indentation level (default 4).

Rust edition to use for parsing (2015, 2018, 2021).

Some configurations are unstable and require nightly. Cannot format macros that produce unparseable output. Comments may be repositioned. Configuration changes may cause large diffs.

rustfmt was developed by Nick Cameron starting in 2015 to provide official formatting for Rust code. It reached 1.0 alongside Rust 1.24 in 2018. The tool was influenced by gofmt and aims to end style debates by providing a single canonical format. It's now maintained by the Rust style team.

cargo(1), rustc(1), clippy(1)