Language cheatsheet

Rust and Cargo 1 Cheatsheet

Cargo and rustup commands for projects, dependencies, testing and releases, with the Rust patterns you reach for most.

Projects and toolchain

Check the Rust version — Print the installed compiler version.
Update Rust — Update the installed toolchains to their latest releases.
Create a new binary project — Create a project with a main.rs and a Cargo.toml.
Create a new library — Create a library crate with a lib.rs.
Initialize Cargo in the current folder — Turn an existing folder into a Cargo package.
Add a compilation target — Install the standard library for another target, here WebAssembly.
Install clippy and rustfmt — Add the linter and formatter to the active toolchain.
Install the nightly toolchain — Install a toolchain for unstable features, then run with cargo +nightly.

Type-check quickly — Check that the code compiles without producing a binary. Much faster than a build.
Build in debug mode — Compile the project with debug info and no optimization.
Build for release — Compile with optimizations into target/release.
Run the project — Build and run the binary.
Run with arguments — Pass arguments to your program after the double dash.
Show a backtrace on panic — Set RUST_BACKTRACE to see where a panic came from.
Delete build output — Remove the target folder to free disk space or force a full rebuild.
Build and open documentation — Build the docs for your crate and its dependencies and open them in a browser.

Add a dependency — Add a crate to Cargo.toml, here serde with its derive macros.
Add a development dependency — Add a crate used only for tests and examples.
Remove a dependency — Remove a crate from Cargo.toml.
Update dependencies — Update Cargo.lock to the newest versions Cargo.toml allows.
Show the dependency tree — Print the dependencies as a tree.
Find duplicate crate versions — List crates that appear in more than one version.
Install a command-line tool — Build and install a crate's binary into ~/.cargo/bin.
Check for vulnerable dependencies — Check Cargo.lock against the RustSec advisory database. Needs cargo-audit installed.

Run the tests — Run unit tests, integration tests and doc tests.
Run matching tests — Run tests whose names contain the text.
Show test output — Show what tests print. Output is hidden for passing tests by default.
Run benchmarks — Run benchmarks. The built-in harness needs the nightly toolchain, so most projects use criterion.
Format the code — Format every file with rustfmt.
Check formatting in CI — Fail if any file isn't formatted, without changing files.
Lint the code — Run clippy and treat warnings as errors, as many CI pipelines do.
Apply compiler suggestions — Automatically apply fixes the compiler suggests.
Check a crate before publishing — Package and verify a crate without uploading it.

Hello world — The smallest runnable Rust program.
Define a struct — Define a type and derive common traits for debugging, copying and comparing.
Propagate errors with ? — Return early with the error when a call fails.
Match on a value — Handle every case of an enum or option.
Transform a collection — Chain iterator adapters, then collect the result.
Async main with Tokio — Run async code with the Tokio runtime. Add it with cargo add tokio --features full.
Use a HashMap — Insert values and read them back.

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