diff --git a/Library/Homebrew/cask/lib/hbc/exceptions.rb b/Library/Homebrew/cask/lib/hbc/exceptions.rb
index 8c9481eec7..31310aea50 100644
--- a/Library/Homebrew/cask/lib/hbc/exceptions.rb
+++ b/Library/Homebrew/cask/lib/hbc/exceptions.rb
@@ -68,7 +68,7 @@ module Hbc
       s = "Command failed to execute!\n"
       s.concat("\n")
       s.concat("==> Failed command:\n")
-      s.concat(@cmd).concat("\n")
+      s.concat(@cmd.join(" ")).concat("\n")
       s.concat("\n")
       s.concat("==> Standard Output of failed command:\n")
       s.concat(@stdout).concat("\n")