Environment variables

  • RUSTUP_HOME (default: ~/.rustup or %USERPROFILE%/.rustup). Sets the root rustup folder, used for storing installed toolchains and configuration options.

  • RUSTUP_TOOLCHAIN (default: none). If set, will override the toolchain used for all rust tool invocations. A toolchain with this name should be installed, or invocations will fail. This can specify custom toolchains, installable toolchains, or the absolute path to a toolchain.

  • RUSTUP_DIST_SERVER (default: https://static.rust-lang.org). Sets the root URL for downloading static resources related to Rust. You can change this to instead use a local mirror, or to test the binaries from the staging directory.

  • RUSTUP_DIST_ROOT deprecated (default: https://static.rust-lang.org/dist). Use RUSTUP_DIST_SERVER instead.

  • RUSTUP_UPDATE_ROOT (default https://static.rust-lang.org/rustup). Sets the root URL for downloading self-update.

  • RUSTUP_IO_THREADS unstable (defaults to reported cpu count). Sets the number of threads to perform close IO in. Set to 1 to force single-threaded IO for troubleshooting, or an arbitrary number to override automatic detection.

  • RUSTUP_TRACE_DIR unstable (default: no tracing). Enables tracing and determines the directory that traces will be written too. Traces are of the form PID.trace. Traces can be read by the Catapult project tracing viewer.

  • RUSTUP_DEBUG unstable. When set, enables rustup’s debug logging.

  • RUSTUP_TERM_COLOR (default: auto). Controls whether colored output is used in the terminal. Set to auto to use colors only in tty streams, to always to always enable colors, or to never to disable colors.

  • RUSTUP_UNPACK_RAM unstable (default free memory or 500MiB if unable to tell, min 210MiB). Caps the amount of RAM rustup will use for IO tasks while unpacking.

  • RUSTUP_NO_BACKTRACE. Disables backtraces on non-panic errors even when RUST_BACKTRACE is set.

  • RUSTUP_PERMIT_COPY_RENAME unstable. When set, allows rustup to fall-back to copying files if attempts to rename result in cross-device link errors. These errors occur on OverlayFS, which is used by Docker. This feature sacrifices some transactions protections and may be removed at any point. Linux only.