How to use the command `rustup default` (with examples)

This article provides a detailed explanation of the rustup default command, which is used to set the default Rust toolchain. The command is a part of the Rustup toolchain manager and allows users to switch between different versions of Rust.

Use case 1: Switch the default Rust toolchain

Code:

rustup default <toolchain>

Motivation:

The default Rust toolchain is the version of Rust that is used by default for all projects on a system. By using the rustup default command, users can easily switch the default toolchain to a different version of Rust. This can be useful when working on different projects that require different versions of Rust or when testing code compatibility with different versions.

Explanation:

The command rustup default is followed by an argument <toolchain>, which specifies the version of Rust to be set as the default toolchain. The <toolchain> argument can be the name of a specific Rust release or a shorthand identifier like stable, beta, or nightly. The available toolchains can be listed using the rustup toolchain list command.

Example output:

$ rustup default nightly-2021-10-10
info: using existing install for 'nightly-2021-10-10'
info: default toolchain set to 'nightly-2021-10-10'

In this example, the default Rust toolchain is switched to the nightly-2021-10-10 version. The command displays an informational message indicating that the existing installation of the specified toolchain is being used, and the default toolchain is successfully set to nightly-2021-10-10.