RUSTUP_LOG (default: none). Enables Rustup’s “custom logging mode”. In this mode, the verbosity of Rustup’s log lines can be specified with tracing_subscriber’sdirective syntax. For example, set RUSTUP_LOG=rustup=DEBUG to receive log lines from rustup itself with a maximal verbosity of DEBUG.
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_ROOTdeprecated (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_VERSION (default: none). Overrides the rustup version (e.g. 1.27.1) to be downloaded when executing rustup-init.sh or rustup self update.
RUSTUP_IO_THREADSunstable (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_DIRunstable (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_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_RAMunstable (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 whenRUST_BACKTRACE is set.
RUSTUP_PERMIT_COPY_RENAMEunstable. 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.
RUSTUP_AUTO_INSTALL (default: 1) When set to 1, installs the active toolchain when it is absent. Set this value to 0 to disable automatic installation.
RUSTUP_HARDLINK_PROXIESunstable. When set, rustup will not attempt to symlink proxies and instead always use hardlinks. If you find this fixes a problem, then please report the issue on the rustup issue tracker.