diff --git a/Library/Homebrew/utils.rb b/Library/Homebrew/utils.rb
index 8ec87b508769bdcc311129f951795947315de604..5fd8fde5bfc9aded365e978d91372efdebe7534b 100644
--- a/Library/Homebrew/utils.rb
+++ b/Library/Homebrew/utils.rb
@@ -88,7 +88,7 @@ end
 def safe_system cmd, *args
   puts "#{cmd} #{args*' '}" if ARGV.verbose?
   fork do
-    exec(cmd, *args) rescue nil
+    exec(cmd, *args.map(&:to_s)) rescue nil
     exit! 1 # never gets here unless exec failed
   end
   Process.wait