--- a/src/ut/lu/lu.go	Sat Jun 23 18:23:54 2018 +0900
+++ b/src/ut/lu/lu.go	Sun Jun 24 06:32:13 2018 +0900
@@ -357,17 +357,21 @@
     }
 }
 
-/* replace:  */
+/* replace:  done. */
 func Replace( s, t string, files []string ) {
     if len( files ) == 0 {
         input := bufio.NewScanner( os.Stdin )
         for input.Scan() {
+            str := strings.Replace( input.Text(), s, t, -1 )
+            fmt.Println( str )
         }
     } else {
         for _, file := range files {
             f, _ := os.Open( file )
             input := bufio.NewScanner( f )
             for input.Scan() {
+                str := strings.Replace( input.Text(), s, t, -1 )
+                fmt.Println( str )
             }
             f.Close()
         }