diff --git a/Library/Homebrew/download_strategy.rb b/Library/Homebrew/download_strategy.rb
index 65bceffa4c928a2f8c20ccf52c68bde4dcdb2c00..e4628511a2dc04b0c60471cec9eba9876ef4b0e9 100644
--- a/Library/Homebrew/download_strategy.rb
+++ b/Library/Homebrew/download_strategy.rb
@@ -609,8 +609,8 @@ class GitDownloadStrategy < VCSDownloadStrategy
   end
 
   def checkout_submodules(dst)
-    sub_cmd = %W{git checkout-index -a -f --prefix=#{dst}/$path/}
-    safe_system 'git', 'submodule', '--quiet', 'foreach', '--recursive', *sub_cmd
+    sub_cmd = "git checkout-index -a -f --prefix=#{dst}/$path/"
+    safe_system 'git', 'submodule', '--quiet', 'foreach', '--recursive', sub_cmd
   end
 end