The script seems to be POSIX-sh (+ local) compatible.

--- a/src/tools/rust-installer/install-template.sh
+++ b/src/tools/rust-installer/install-template.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 # Copyright 2014 The Rust Project Developers. See the COPYRIGHT
 # file at the top-level directory of this distribution and at
 # http://rust-lang.org/COPYRIGHT.