diff --git a/doc/contributing/building_ruby.md b/doc/contributing/building_ruby.md
index d2f175f4a9..ace5fbed37 100644
--- a/doc/contributing/building_ruby.md
+++ b/doc/contributing/building_ruby.md
@@ -39,7 +39,7 @@
 5. Optional: If you are frequently building Ruby, disabling documentation will reduce the time it takes to `make`:
 
     ``` shell
-    ../configure --disable-install-doc
+    ../configure --prefix="${HOME}/.rubies/ruby-master" --disable-install-doc
     ```
 
 6. [Run tests](testing_ruby.md) to confirm your build succeeded