Implement environment variable substitution for unix platforms
I want to be able to use this to redirect the bazel config file based
on the environment, for integration with our existing
environment-based mechanisms for selecting build configurations.
I found some opinions in comments which said this was too difficult,
which I have amended.
Closes #7318.
PiperOrigin-RevId: 237467945
diff --git a/site/docs/guide.html b/site/docs/guide.html
index a393989..b1af89a 100644
--- a/site/docs/guide.html
+++ b/site/docs/guide.html
@@ -858,11 +858,15 @@
<li>
Unless the <code class='flag'>--nosystem_rc</code> is present, Bazel looks for
the system .bazelrc file: on Unix, it lives at <code>/etc/bazel.bazelrc</code>,
- and on Windows at <code>%%ProgramData%%/bazel.bazelrc</code>.
+ and on Windows at <code>%ProgramData%/bazel.bazelrc</code>.
If another system-specified location is required, this value can be
changed by setting <code>BAZEL_SYSTEM_BAZELRC_PATH</code> in
<code>src/main/cpp:option_processor</code> and using this custom Bazel binary.
+
+ The system-specified location may contain environment variable
+ substitutions, as <code>%var_name%</code> on Windows
+ or <code>${var_name}</code> on Unix.
</li>
<li>
Unless the <code class='flag'>--noworkspace_rc</code> is present, Bazel looks
