jruby - take advantage of FileUtils being included in Formula.

Formula/jruby.rb

@@ -1,27 +1,25 @@
 require 'formula'
 
-# My god! 20,000 files?!
-# TODO trim that a bit? Seems crazy.
-
 class Jruby < Formula
   url 'http://jruby.kenai.com/downloads/1.4.0/jruby-bin-1.4.0.tar.gz'
   homepage 'http://www.jruby.org'
   md5 'f37322c18e9134e91e064aebb4baa4c7'
 
   def install
+    # Remove Windows files
+    rm Dir['bin/*.{bat,dll,exe}']
+
+    # Prefix a 'j' on some commands
     Dir.chdir 'bin' do
-      FileUtils.rm Dir['*.bat']
-      FileUtils.rm Dir['*.exe']
-      FileUtils.rm Dir['*.dll']
       Dir['*'].each do |file|
-        FileUtils.mv file, "j#{file}" unless file.match /^[j_]/
+        mv file, "j#{file}" unless file.match /^[j_]/
       end
     end
-    
-    # Only keep the MacOSX native libraries
+
+    # Only keep the OS X native libraries
     Dir.chdir 'lib/native' do
       Dir['*'].each do |file|
-        FileUtils.rm_rf file unless file == 'darwin'
+        rm_rf file unless file == 'darwin'
       end
     end