diff --git a/http.go b/http.go
index 1b9d0c9..a56a456 100644
--- a/http.go
+++ b/http.go
@@ -73,8 +73,17 @@ func okHandler(w http.ResponseWriter, r *http.Request) {
 		for _, dir := range c.Dirs {
 			log.Info("append dir", dir)
 			fmt.Fprintln(w, "append dir", dir)
-			me.dirs = append(me.dirs, dir)
+			var found bool = false
+			for _, d := range me.dirs {
+				if d == dir {
+					found = true
+				}
+			}
+			if ! found {
+				me.dirs = append(me.dirs, dir)
+			}
 		}
+		return
 	}
 
 	if tmp == "/start" {