rustc — Rust compiler

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The official compiler that turns Rust sources into a single binary.

Basic Information

What is this command?

rustc compiles Rust sources directly. Its ownership and borrow checks run at compile time, blocking many memory-safety issues before execution.

In practice cargo manages dependencies and build settings, while rustc serves single-file experiments or fine-grained control. Optimization and debug info are set with -C options.

What problems does it solve?

• Trying Rust syntax in a single file
• Building a binary without cargo
• Controlling optimization and debug options directly
• Learning from compiler diagnostics

Key features

Single-file build

Compile one source into a binary.

• When to use: Testing syntax or an algorithm
• What you get: You get a standalone binary.
• Limitations: External crates must be linked manually.

Optimization level

-C opt-level controls optimization strength.

• When to use: Benchmarking or release builds
• What you get: Balance runtime performance against build time.
• Limitations: Heavy optimization makes debugging harder.

Diagnostics

Explains ownership and borrow errors in detail.

• When to use: Understanding why compilation failed
• What you get: You get guidance on how to fix it.
• Limitations: Messages can be long for newcomers.

Installation and usage

Check whether it is installed

rustc --version

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh source "$HOME/.cargo/env"

Real-world examples

Compile one file

Build a binary with default optimization.

rustc main.rs -o app
./app

Release optimization

Raise optimization for distribution.

rustc -C opt-level=3 main.rs -o app

Include debug info

Build with symbols so a debugger can inspect variables.

rustc -g main.rs -o app-debug