diff --git a/README.md b/README.md
index f8648a5..4315b71 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,9 @@
 # sniffer
 
+[![GoDoc](https://godoc.org/github.com/chenjiandongx/sniffer?status.svg)](https://godoc.org/github.com/chenjiandongx/sniffer)
+[![Go Report Card](https://goreportcard.com/badge/github.com/chenjiandongx/sniffer)](https://goreportcard.com/report/github.com/chenjiandongx/sniffer)
+[![License](https://img.shields.io/badge/License-MIT-brightgreen.svg)](https://opensource.org/licenses/MIT)
+
 > *A modern alternative network traffic sniffer inspired by [bandwhich](https://github.com/imsnif/bandwhich)(Rust) and [nethogs](https://github.com/raboof/nethogs)(C++).*
 
 https://user-images.githubusercontent.com/19553554/141692419-da8b63e1-e936-4d14-8ff5-5893e20a1f27.mov
diff --git a/conn_darwin.go b/conn_darwin.go
index 553ab9b..a08bac3 100644
--- a/conn_darwin.go
+++ b/conn_darwin.go
@@ -13,12 +13,13 @@ import (
 )
 
 type lsofConn struct {
-	invoker LsofInvoker
+	invoker lsofInvoker
 }
 
-type LsofInvoker struct{}
+type lsofInvoker struct{}
 
-func (i LsofInvoker) Exec() ([]byte, error) {
+// Exec executes the command and return the output bytes of it.
+func (i lsofInvoker) Exec() ([]byte, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 	defer cancel()
 
diff --git a/dns.go b/dns.go
index 537e3f3..9998223 100644
--- a/dns.go
+++ b/dns.go
@@ -50,6 +50,7 @@ func (c *DNSResolver) Close() {
 	c.wg.Wait()
 }
 
+// Lookup resolve remote ip to the domains.
 func (c *DNSResolver) Lookup(ip string) string {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
@@ -62,6 +63,10 @@ func (c *DNSResolver) Lookup(ip string) string {
 		return ip
 	}
 
+	if len(addrs) == 1 {
+		return addrs[0]
+	}
+
 	sort.Strings(addrs)
 	return addrs[0]
 }
diff --git a/ui.go b/ui.go
index 5f6c887..268e287 100644
--- a/ui.go
+++ b/ui.go
@@ -287,18 +287,12 @@ func (pv *PlotViewer) Shift() {
 	pv.shiftIdx++
 	width, height := termui.TerminalDimensions()
 	pv.grid = pv.newGrid(width, height)
-	if pv.count <= 1 {
-		return
-	}
-	termui.Render(pv.grid)
+	pv.render()
 }
 
 func (pv *PlotViewer) Resize(width, height int) {
 	pv.grid = pv.newGrid(width, height)
-	if pv.count <= 1 {
-		return
-	}
-	termui.Render(pv.grid)
+	pv.render()
 }
 
 func (pv *PlotViewer) Render(stats interface{}) {
@@ -313,6 +307,10 @@ func (pv *PlotViewer) Render(stats interface{}) {
 	pv.updatePackets(data)
 	pv.updateBytes(data)
 	pv.updateConnections(data)
+	pv.render()
+}
+
+func (pv *PlotViewer) render() {
 	if pv.count <= 1 {
 		return
 	}