Fix formatter and output

config.go

@@ -147,7 +147,11 @@ func getFiles() []string {
 		if err != nil {
 			panic(err)
 		}
-		matches = append(matches, m...)
+		for _, f := range m {
+			if strings.HasSuffix(f, ".go") {
+				matches = append(matches, f)
+			}
+		}
 	}
 
 	if excludeGlobs == "" {

formatter/default.go

@@ -20,7 +20,7 @@ func (f *Default) Name() string {
 // Format formats the failures gotten from the lint.
 func (f *Default) Format(failures <-chan lint.Failure, config lint.RulesConfig) (string, error) {
 	for failure := range failures {
-		fmt.Printf("%v%v: %s\n", failure.GetFilename(), failure.Position.Start, failure.Failure)
+		fmt.Printf("%v: %s\n", failure.Position.Start, failure.Failure)
 	}
 	return "", nil
 }

main.go

@@ -60,7 +60,9 @@ func main() {
 
 	close(formatChan)
 	<-exitChan
-	fmt.Println(output)
+	if output != "" {
+		fmt.Println(output)
+	}
 
 	os.Exit(exitCode)
 }