> ## Documentation Index
> Fetch the complete documentation index at: https://docs.solved.gg/llms.txt
> Use this file to discover all available pages before exploring further.

# Toolchains

> Install and select Rust toolchains with rusty env (rustup-like, Linux).

rusty manages Rust toolchains under `$RUSTY_HOME`, similar in spirit to rustup, but with a **minimal default install** and no cargo-by-default.

## Commands

```bash theme={null}
rusty env install <id> [target...]   # install toolchain (+ optional targets/components)
rusty env uninstall <id>             # remove a toolchain
rusty env list                       # installed toolchains
rusty env show                       # active toolchain + host
rusty env which <prog>               # path to prog in the active toolchain
rusty env use <id>                   # set default toolchain
```

`<id>` is a channel or toolchain name such as `stable`, `nightly`, or a specific version string accepted by the installer.

## Default components

A default install is **`rustc` + `rust-std` only**. Cargo is **not** downloaded unless you ask:

```bash theme={null}
rusty env install stable cargo
```

Reasons:

* Core rusty verbs do not require the cargo binary.
* Interop verbs that need cargo stay explicit and fail closed if cargo is missing.

## Proxies and PATH

After `rusty env use`:

1. Shims appear (or are updated) under `$RUSTY_HOME/bin`.
2. Put that directory on `PATH` so `rustc` / `rustdoc` / `rustfmt` resolve through rusty.
3. Override per process with `RUSTY_TOOLCHAIN` or `+toolchain` where supported.

```bash theme={null}
export PATH="${RUSTY_HOME:-$HOME/.rusty}/bin:$PATH"
rusty env which rustc
```

## During builds

When rusty prepares a build environment it may set:

| Variable             | Typical value                   |
| -------------------- | ------------------------------- |
| `CARGO_HOME`         | `$RUSTY_HOME/cargo-home`        |
| `CARGO_TARGET_DIR`   | `<workspace>/.rusty/target`     |
| `CARGO_PROFILE`      | `debug` or `release`            |
| `RUSTC_WRAPPER`      | `$RUSTY_HOME/bin/rusty-wrapper` |
| `RUSTY_PROJECT_ROOT` | workspace root                  |

These keep cargo-compatible tools and build scripts oriented at the managed layout without making cargo the package manager.

## Related

* [Environment variables](/rusty/reference/environment)
* [Install](/rusty/install)


## Related topics

- [CLI reference](/rusty/0.0.1-dev/reference/cli.md)
- [Quickstart](/rusty/0.0.1-dev/quickstart.md)
- [Install](/rusty/0.0.1-dev/install.md)
- [Introduction](/rusty/0.0.1-dev/index.md)
- [How rusty works](/rusty/0.0.1-dev/concepts/overview.md)