diff --git a/docs/Formula-Cookbook.md b/docs/Formula-Cookbook.md
index bb3ad33dcf16e76f5d5030d4c35457149eb19008..ac9d8cc7966aa93c506749985cf8468558dd1218 100644
--- a/docs/Formula-Cookbook.md
+++ b/docs/Formula-Cookbook.md
@@ -783,6 +783,8 @@ The symlinks created by `install_symlink` are guaranteed to be relative. `ln_s`
 
 For example, Ruby 1.9鈥檚 gems should be installed to `var/lib/ruby/` so that gems don鈥檛 need to be reinstalled when upgrading Ruby. You can usually do this with symlink trickery, or *better* a configure option.
 
+Another example would be configuration files that should not be overwritten on package upgrades. If after installation you find that to-be-persisted configuration files are not copied but instead *symlinked* into `/usr/local/etc/` from the Cellar, this can often be rectified by passing an appropriate argument to the package鈥檚 configure script. That argument will vary depending on a given package鈥檚 configure script and/or Makefile, but one example might be: `--sysconfdir=#{etc}`
+
 ### launchd plist files
 
 Homebrew provides two Formula methods for launchd plist files. [`plist_name`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#plist_name-instance_method) will return e.g. `homebrew.mxcl.<formula>` and [`plist_path`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#plist_path-instance_method) will return e.g. `/usr/local/Cellar/foo/0.1/homebrew.mxcl.foo.plist`.