Command line
  → rustup binary (multi-call: arg0 selects mode)
    → rustup_mode    : rustup <subcommand> ...   (management)
    → proxy_mode     : cargo / rustc / ...        (tool dispatch)
    → setup_mode     : rustup-init                (installer)
      → toolchain resolution
        1. +toolchain shorthand
        2. RUSTUP_TOOLCHAIN env var
        3. rustup override (dir override, closest wins)
        4. rust-toolchain.toml / rust-toolchain file (closest wins)
        5. default toolchain
      → install-on-run (if RUSTUP_AUTO_INSTALL=1)
      → exec real toolchain binary with configured env

Sub-Resources

Load the reference that matches your task. When in doubt, load multiple references.

Keywords	Reference
install, uninstall, update, default, check, show, set, home, completions, help, global flags, --verbose, --quiet, --version, --no-self-update, top-level commands	references/cli.md
toolchain, install, uninstall, list, link, custom toolchain, channel, stable, beta, nightly, versioned, dated, target triple, host, spec syntax, toolchain name	references/toolchain.md
target, cross-compilation, target add, target list, target remove, rust-std, std library, linker, --target, --toolchain, --installed	references/target.md
component, add, remove, list, rustc, cargo, rustfmt, rust-docs, rust-analyzer, clippy, miri, rust-src, llvm-tools, rls, --target, --toolchain, profile, minimal, default, complete	references/component.md
override, override set, override unset, override list, rust-toolchain.toml, rust-toolchain file, toolchain resolution, precedence, RUSTUP_TOOLCHAIN, +toolchain, settings.toml, directory override	references/override.md
proxy, shim, cargo, rustc, rustdoc, rustfmt, rust-analyzer, clippy-driver, cargo-clippy, cargo-miri, rls, rust-gdb, rust-lldb, multi-call binary, rustup run, +toolchain shorthand, which, doc, man, install-on-run, recursion protection	references/proxy.md
environment variables, RUSTUP_HOME, CARGO_HOME, RUSTUP_TOOLCHAIN, RUSTUP_DIST_SERVER, RUSTUP_UPDATE_ROOT, RUSTUP_AUTO_INSTALL, RUSTUP_LOG, RUSTUP_TERM_COLOR, RUSTUP_IO_THREADS, settings.toml, configuration	references/environment.md

Quick Guide

How do I install a toolchain? → references/toolchain.md
How do I switch the default toolchain? → references/cli.md
How do I cross-compile to another target? → references/target.md
How do I add clippy/rustfmt/rust-analyzer? → references/component.md
How do I pin a toolchain per project? → references/override.md
How does cargo +nightly build work? → references/proxy.md
How does rustup decide which toolchain to use? → references/override.md
How do I run a command with a specific toolchain? → references/proxy.md
What components and profiles are available? → references/component.md
What environment variables does rustup use? → references/environment.md
How do I generate shell completions for rustup? → references/cli.md
How do I update or uninstall rustup itself? → references/cli.md

Cross-Project References

For cargo (the package manager/build tool proxied by rustup), see cargo's own documentation. This skill covers only rustup's proxy dispatch and environment setup for cargo, not cargo's command surface.
For rust-analyzer as an LSP server (capabilities, configuration, extensions), see the rust-analyzer documentation. This skill covers only the rustup component/proxy aspect.

rustup

rustup In-Depth Reference

Data Flow