Rust Cargo Cheat Sheet
Reference for Cargo commands, Cargo.toml structure, dependency management, workspaces, and common cargo subcommands for building and testing Rust projects.
2 PagesBeginnerApr 12, 2026
Basic Commands
The core cargo workflow for building and running projects.
bash
cargo new my_project # Create a new binary projectcargo new --lib my_lib # Create a new library projectcargo build # Compile in debug mode (target/debug)cargo build --release # Compile with optimizations (target/release)cargo run # Build and run the binarycargo run -- arg1 arg2 # Pass arguments to the binarycargo check # Fast type-check without producing a binarycargo test # Run all testscargo test test_name # Run tests matching a name filter
Cargo.toml
The project manifest that declares metadata and dependencies.
yaml
[package]name = "my_project"version = "0.1.0"edition = "2021"[dependencies]serde = { version = "1.0", features = ["derive"] }tokio = { version = "1", features = ["full"] }rand = "0.8"[dev-dependencies]criterion = "0.5"[profile.release]opt-level = 3lto = true
Common Subcommands
Frequently used cargo tooling commands.
- cargo fmt- Formats source code according to rustfmt rules
- cargo clippy- Runs the Clippy linter for idiomatic-code suggestions and common mistakes
- cargo doc --open- Builds and opens crate documentation in a browser
- cargo add <crate>- Adds a dependency to Cargo.toml (Cargo 1.62+)
- cargo update- Updates dependencies in Cargo.lock to the latest compatible versions
- cargo publish- Publishes the crate to crates.io
- cargo tree- Prints the dependency tree, useful for debugging version conflicts
- cargo clean- Removes the target directory build artifacts
Workspaces
Managing multiple related crates in a single repository.
toml
# Top-level Cargo.toml for a multi-crate workspace[workspace]members = [ "app", "core", "cli",]resolver = "2"[workspace.dependencies]serde = { version = "1.0", features = ["derive"] }# cargo build --workspace # Build every crate in the workspace# cargo test -p core # Run tests only for the "core" package
Dependency Version Specs
Syntax for constraining dependency versions in Cargo.toml.
- "1.2.3"- Caret requirement (default); allows updates that don't change the leftmost non-zero digit
- "=1.2.3"- Exact version requirement, no automatic updates
- "~1.2"- Tilde requirement; allows patch-level updates only (1.2.x)
- git = "url"- Pulls a dependency directly from a Git repository
- path = "../local-crate"- Uses a local path dependency, common in workspaces
- features = [...]- Enables optional, opt-in functionality exposed by the dependency
- default-features = false- Disables a dependency's default feature set to reduce compile time/size
build.rs Build Scripts
A build.rs file runs before compilation to generate code, link native libraries, or set cfg flags.
rust
// build.rs (placed at the crate root, next to Cargo.toml)fn main() { // Re-run this script only if build.rs itself or the given file changes println!("cargo:rerun-if-changed=build.rs"); println!("cargo:rerun-if-changed=src/schema.proto"); // Link a native library found on the system println!("cargo:rustc-link-lib=z"); // Emit a custom cfg flag consumable via #[cfg(has_feature_x)] println!("cargo:rustc-cfg=has_feature_x"); // Pass a value to the crate as an env var at compile time println!("cargo:rustc-env=BUILD_TIMESTAMP={}", chrono_like_stamp());}fn chrono_like_stamp() -> String { "2026-07-21".to_string()}
Feature Flags & Conditional Compilation
Cargo features toggle optional code paths and dependencies, gated with #[cfg(feature = "...")].
toml
[features]default = ["std"]std = []async = ["dep:tokio"]full = ["std", "async", "serde"]serde = ["dep:serde"][dependencies]tokio = { version = "1", optional = true }serde = { version = "1", optional = true }# In code:# #[cfg(feature = "async")]# async fn fetch() { /* ... */ }## cargo build --features async# cargo build --no-default-features --features std
Advanced Cargo Tooling
Ecosystem subcommands beyond the built-in ones, installed via cargo install.
- cargo audit- Scans Cargo.lock against the RustSec advisory database for known-vulnerable dependencies
- cargo deny check- Enforces license, ban, and duplicate-version policies defined in deny.toml
- cargo expand- Prints the fully macro-expanded source, invaluable for debugging derive/proc macros
- cargo udeps- Detects unused dependencies declared in Cargo.toml (requires nightly)
- cargo nextest run- Faster, more parallel test runner with better output than the built-in cargo test
- cargo bench- Runs benchmarks, typically backed by the criterion crate on stable Rust
- cargo-cross- Cross-compiles for a target triple using a preconfigured Docker toolchain image
.cargo/config.toml
Project- or user-level configuration for build targets, aliases, and registry mirrors.
toml
# .cargo/config.toml (project root or ~/.cargo/config.toml)[build]target = "x86_64-unknown-linux-musl"rustflags = ["-C", "target-cpu=native"][alias]b = "build"t = "test"ci = "check --all-targets --all-features"[target.x86_64-unknown-linux-gnu]linker = "clang"[net]git-fetch-with-cli = true
Target-Specific & Workspace-Inherited Dependencies
Dependencies can be gated per platform, and workspace members can inherit shared versions.
toml
# Only pulled in when compiling for Windows[target.'cfg(windows)'.dependencies]winapi = { version = "0.3", features = ["winuser"] }# Only pulled in when compiling for Unix-like targets[target.'cfg(unix)'.dependencies]libc = "0.2"# In a member crate's Cargo.toml, inherit versions from [workspace.dependencies][dependencies]serde = { workspace = true }version = { workspace = true }
Pro Tip
Commit Cargo.lock for binary applications (reproducible builds) but omit it for libraries, so downstream consumers resolve dependency versions against their own lockfile.
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