rustup

TLDR

Install the nightly toolchain for your system

$ rustup install nightly

Switch the default toolchain to nightly so that the cargo and rustc commands will use it

$ rustup default nightly

Use the nightly toolchain when inside the current project but leave global settings unchanged

$ rustup override set nightly

Update all toolchains

$ rustup update

List installed toolchains

$ rustup show

Run cargo build with a certain toolchain

$ rustup run [toolchain] cargo build

Open the local Rust documentation in the default web browser

$ rustup doc