diff --git a/Build/EvilLinker.hs b/Build/EvilLinker.hs
index a6176754cd..f852b81199 100644
--- a/Build/EvilLinker.hs
+++ b/Build/EvilLinker.hs
@@ -114,7 +114,7 @@ getOutput :: String -> [String] -> Maybe [(String, String)] -> IO (String, Bool)
 getOutput cmd params env = do
 	putStrLn $ unwords [cmd, show params]
 	out@(s, ok) <- processTranscript' cmd params env Nothing
-	putStrLn $ unwords [cmd, "finished", show ok, "output size:", length s]
+	putStrLn $ unwords [cmd, "finished", show ok, "output size:", show (length s)]
 	return out
 
 runParser' :: Parser a -> String -> String -> a