What is the difference between binaries in ~/.rustup vs ~/.cargo?

Question

I just installed Rust with rustup on MacOS and noticed that there are two rustc and two cargo binaries:

• ~/.cargo/bin/rustc (cargo)
• ~/.rustup/toolchains/stable-x86_64-apple-darwin/bin/rustc (cargo)

Their versions are exactly the same, but diff shows there exists some difference. So why are there two different rustc (cargo) binaries and which one should I use?

Scotia

Answer 1

The reason there are two files named rustc is because rustup is a toolchain multiplexer. It lets you install many versions of Rust and easily switch between them.

The binary installed at ~/.cargo/bin/rustc proxies to the current toolchain that you have selected. Each installed compiler is kept under the toolchains directory.

Although the compiler in the toolchains directory appears to be a smaller file, that's only because it's dynamically linked instead of statically linked.

More information can be found on rustup's README.

Crutchfield

So the binaries in .cargo are basically proxies to the current toolchain, right? – Scotia

@ZizhengTai Yes, exactly. – Crutchfield

@squiguy: You might want to expand your answer to explain why the files are different. – Kanchenjunga

@MatthieuM. Done. Feel free to edit my answer(s) in the future. – Crutchfield

@ZizhengTai to clarify, the cargo, rust-gdb, rust-lldb, rustc, rustdoc, and rustup binaries in .cargo/bin/ are all the same file. The first 5 all proxy to the relevant toolchain file. – Gas