From bc19b73e346b227a8d9126480152a50baaebbe23 Mon Sep 17 00:00:00 2001
From: Hiroshi SHIBATA <hsbt@ruby-lang.org>
Date: Wed, 11 Jun 2025 14:14:35 +0900
Subject: [PATCH] Added document for RAKEOPT

Fixed #439
---
 doc/command_line_usage.rdoc | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/doc/command_line_usage.rdoc b/doc/command_line_usage.rdoc
index 105d6c8e9..c1ff39d5b 100644
--- a/doc/command_line_usage.rdoc
+++ b/doc/command_line_usage.rdoc
@@ -153,6 +153,19 @@ Options are:
 [<tt>--no-deprecation-warnings</tt> (-X)]
     Do not display the deprecation warnings.
 
+== Environment Variables
+
+[<tt>RAKEOPT</tt>]
+    Command line options can be specified in the <tt>RAKEOPT</tt>
+    environment variable. These options will be processed as if they
+    were given on the command line. This is useful for setting default
+    options that you want to use with every rake invocation.
+
+    For example, setting:
+        export RAKEOPT="-s --trace"
+
+    would cause rake to run silently with tracing enabled by default.
+
 In addition, any command line option of the form
 <em>VAR</em>=<em>VALUE</em> will be added to the environment hash
 <tt>ENV</tt> and may be tested in the Rakefile.