cargo-fmt

Format Rust source code with rustfmt

TLDR

Format current package

$ cargo fmt

Format all packages in workspace

$ cargo fmt --all

Check formatting without changes

$ cargo fmt --check

Format specific package

$ cargo fmt -p [package]

Show diff of changes

$ cargo fmt -- --emit diff

Format with verbose output

$ cargo fmt --verbose

SYNOPSIS

cargo fmt [options] [-- rustfmtoptions_]

DESCRIPTION

cargo fmt formats all bin and lib files of the current crate using rustfmt. Formats .rs files in src/, tests/, examples/, and integration tests. Reformats code in-place by default.

PARAMETERS

--all

Format all packages in workspace

--check

Check formatting without modifying files (for CI)

-p, --package name

Format specific package

--manifest-path path

Path to Cargo.toml

-v, --verbose

Verbose output

-q, --quiet

Suppress output

-- --emit mode

Output mode: files, stdout, diff

-- --edition year

Override Rust edition

CONFIGURATION

Create rustfmt.toml or .rustfmt.toml in project root:

$ max_width = 100
tab_spaces = 4
edition = "2021"

CI INTEGRATION

$ cargo fmt --all -- --check

Exits with non-zero code if formatting issues found.

CAVEATS

Edition automatically read from Cargo.toml. Direct rustfmt defaults to 2015 edition. Set style_edition in config for consistency.