diff --git a/hosts/hosts.go b/hosts/hosts.go
index b056de2..0eaf37e 100644
--- a/hosts/hosts.go
+++ b/hosts/hosts.go
@@ -28,21 +28,151 @@ func SystemHostpath() string {
 	return `/etc/hosts`
 }
 
+var defaultParser = NewHosts()
+
+func ParseHosts(hostPath string) error {
+	return defaultParser.Parse(hostPath)
+}
+
+func Parse() error {
+	return defaultParser.Parse(SystemHostpath())
+}
+
+func List() []*HostNode {
+	return defaultParser.List()
+}
+
+func ListHosts() map[string][]string {
+	return defaultParser.ListHosts()
+}
+
+func ListIPs() map[string][]string {
+	return defaultParser.ListIPs()
+}
+
+func ListByHost(host string) []*HostNode {
+	return defaultParser.ListByHost(host)
+}
+
+func ListIPsByHost(host string) []string {
+	return defaultParser.ListIPsByHost(host)
+}
+
+func ListFirstIPByHost(host string) string {
+	return defaultParser.ListFirstIPByHost(host)
+}
+
+func ListByIP(ip string) []*HostNode {
+	return defaultParser.ListByIP(ip)
+}
+
+func ListHostsByIP(ip string) []string {
+	return defaultParser.ListHostsByIP(ip)
+}
+
+func ListFirstHostByIP(ip string) string {
+	return defaultParser.ListFirstHostByIP(ip)
+}
+
+func AddHosts(ip string, hosts ...string) error {
+	return defaultParser.AddHosts(ip, hosts...)
+}
+
+func AddHostsComment(comment string, ip string, hosts ...string) error {
+	return defaultParser.AddHostsComment(comment, ip, hosts...)
+}
+
+func RemoveIPHosts(ip string, hosts ...string) error {
+	return defaultParser.RemoveIPHosts(ip, hosts...)
+}
+
+func RemoveIPs(ips ...string) error {
+	return defaultParser.RemoveIPs(ips...)
+}
+
+func RemoveHosts(hosts ...string) error {
+	return defaultParser.RemoveHosts(hosts...)
+}
+
+func SetIPHosts(ip string, hosts ...string) error {
+	return defaultParser.SetIPHosts(ip, hosts...)
+}
+
+func SetHostIPs(host string, ips ...string) error {
+	return defaultParser.SetHostIPs(host, ips...)
+}
+
+func InsertNodes(node *HostNode, before bool, comment string, ip string, hosts ...string) error {
+	return defaultParser.InsertNodeByData(node, before, comment, ip, hosts...)
+}
+
+func SaveAs(path string) error {
+	return defaultParser.SaveAs(path)
+}
+
+func Save() error {
+	return defaultParser.Save()
+}
+
+func Build() ([]byte, error) {
+	return defaultParser.Build()
+}
+
+func GetFirstNode() (*HostNode, error) {
+	return defaultParser.GetFirstNode()
+}
+
+func GetNode(nodeID uint64) (*HostNode, error) {
+	return defaultParser.GetNode(nodeID)
+}
+
+func GetNextNode(nodeID uint64) (*HostNode, error) {
+	return defaultParser.GetNextNode(nodeID)
+}
+
+func GetLastNode(nodeID uint64) (*HostNode, error) {
+	return defaultParser.GetLastNode(nodeID)
+}
+
+func GetLatestNode() (*HostNode, error) {
+	return defaultParser.GetLatestNode()
+}
+
+func DeleteNode(node *HostNode) error {
+	return defaultParser.DeleteNode(node)
+}
+
+func DeleteNodeByUID(uid uint64) error {
+	return defaultParser.DeleteNodeByUID(uid)
+}
+
+func AddNode(node *HostNode) error {
+	return defaultParser.AddNode(node)
+}
+
+func InsertNode(node *HostNode) error {
+	return defaultParser.InsertNode(node)
+}
+
+func UpdateNode(node *HostNode) error {
+	return defaultParser.UpdateNode(node)
+}
+
 type HostNode struct {
 	uid         uint64
 	nextuid     uint64
 	lastuid     uint64
-	IP          string
-	Host        []string
-	Comment     string
-	Original    string
-	OnlyComment bool
-	Valid       bool
+	ip          string
+	host        []string
+	comment     string
+	original    string
+	onlyComment bool
+	valid       bool
 }
 type Host struct {
 	idx      uint64
 	hostPath string
-	nextUid  uint64
+	firstUid uint64
 	lastUid  uint64
 	fulldata map[uint64]*HostNode
 	hostData map[string][]*HostNode
@@ -61,6 +191,9 @@ func NewHosts() *Host {
 func (h *Host) Parse(hostPath string) error {
 	h.Lock()
 	defer h.Unlock()
+	h.idx = 0
+	h.firstUid = 0
+	h.lastUid = 0
 	h.hostPath = hostPath
 	h.fulldata = make(map[uint64]*HostNode)
 	h.hostData = make(map[string][]*HostNode)
@@ -94,14 +227,14 @@ func (h *Host) parse() error {
 		data.lastuid = h.idx - 1
 		data.nextuid = h.idx + 1
 		h.fulldata[data.uid] = &data
-		if h.nextUid == 0 {
-			h.nextUid = h.idx
+		if h.firstUid == 0 {
+			h.firstUid = h.idx
 		}
-		if data.Valid {
-			for _, v := range data.Host {
+		if data.valid {
+			for _, v := range data.host {
 				h.hostData[v] = append(h.hostData[v], &data)
 			}
-			h.ipData[data.IP] = append(h.ipData[data.IP], &data)
+			h.ipData[data.ip] = append(h.ipData[data.ip], &data)
 		}
 	}
 
@@ -110,14 +243,15 @@ func (h *Host) parse() error {
 
 func (h *Host) parseLine(data string) (HostNode, error) {
 	var res = HostNode{
-		Original: data,
+		original: data,
 	}
 	if len(data) == 0 {
 		return res, fmt.Errorf("empty line")
 	}
 	if data[0] == '#' {
-		res.Comment = data
-		res.OnlyComment = true
+		res.comment = data
+		res.onlyComment = true
+		res.valid = true
 		return res, nil
 	}
 	var dataArr []string
@@ -155,16 +289,16 @@ func (h *Host) parseLine(data string) (HostNode, error) {
 	for k, v := range dataArr {
 		switch k {
 		case 0:
-			res.IP = v
+			res.ip = v
 		default:
 			if strings.HasPrefix(v, "#") {
-				res.Comment = v
+				res.comment = v
 			} else {
-				res.Host = append(res.Host, v)
+				res.host = append(res.host, v)
 			}
 		}
 	}
-	res.Valid = true
+	res.valid = true
 	return res, nil
 }
 
@@ -172,7 +306,7 @@ func (h *Host) List() []*HostNode {
 	h.RLock()
 	defer h.RUnlock()
 	var res []*HostNode
-	nextUid := h.nextUid
+	nextUid := h.firstUid
 	for {
 		if nextUid == 0 {
 			break
@@ -183,6 +317,36 @@ func (h *Host) List() []*HostNode {
 	return res
 }
 
+func (h *Host) ListHosts() map[string][]string {
+	h.RLock()
+	defer h.RUnlock()
+	if h.hostData == nil {
+		return nil
+	}
+	var res = make(map[string][]string)
+	for k, v := range h.hostData {
+		for _, vv := range v {
+			res[k] = append(res[k], vv.ip)
+		}
+	}
+	return res
+}
+
+func (h *Host) ListIPs() map[string][]string {
+	h.RLock()
+	defer h.RUnlock()
+	if h.ipData == nil {
+		return nil
+	}
+	var res = make(map[string][]string)
+	for k, v := range h.ipData {
+		for _, vv := range v {
+			res[k] = append(res[k], vv.host...)
+		}
+	}
+	return res
+}
+
 func (h *Host) ListByHost(host string) []*HostNode {
 	h.RLock()
 	defer h.RUnlock()
@@ -200,7 +364,7 @@ func (h *Host) ListIPsByHost(host string) []string {
 	}
 	var res []string
 	for _, v := range h.hostData[host] {
-		res = append(res, v.IP)
+		res = append(res, v.ip)
 	}
 	return res
 }
@@ -212,7 +376,7 @@ func (h *Host) ListFirstIPByHost(host string) string {
 		return ""
 	}
 	for _, v := range h.hostData[host] {
-		return v.IP
+		return v.ip
 	}
 	return ""
 }
@@ -228,6 +392,7 @@ func (h *Host) ListByIP(ip string) []*HostNode {
 
 func (h *Host) ListHostsByIP(ip string) []string {
 	h.RLock()
+	defer h.RUnlock()
 	return h.listHostsByIP(ip)
 }
 
@@ -237,7 +402,7 @@ func (h *Host) listHostsByIP(ip string) []string {
 	}
 	var res []string
 	for _, v := range h.ipData[ip] {
-		res = append(res, v.Host...)
+		res = append(res, v.host...)
 	}
 	return res
 }
@@ -249,8 +414,8 @@ func (h *Host) ListFirstHostByIP(ip string) string {
 		return ""
 	}
 	for _, v := range h.ipData[ip] {
-		if len(v.Host) > 0 {
-			return v.Host[0]
+		if len(v.host) > 0 {
+			return v.host[0]
 		}
 	}
 	return ""
@@ -277,12 +442,12 @@ func (h *Host) RemoveIPHosts(ip string, hosts ...string) error {
 cntfor:
 	for _, v := range ipInfo {
 		for _, host := range hosts {
-			if len(v.Host) == 1 && v.Host[0] == host {
+			if len(v.host) == 1 && v.host[0] == host {
 				delete(h.ipData, ip)
 				if v.lastuid != 0 {
 					h.fulldata[v.lastuid].nextuid = v.nextuid
 				} else {
-					h.nextUid = v.nextuid
+					h.firstUid = v.nextuid
 				}
 				if v.nextuid != 0 {
 					h.fulldata[v.nextuid].lastuid = v.lastuid
@@ -290,7 +455,7 @@ cntfor:
 					h.lastUid = v.lastuid
 				}
 				var newHostData []*HostNode
-				for _, vv := range h.hostData[v.Host[0]] {
+				for _, vv := range h.hostData[v.host[0]] {
 					if vv.uid != v.uid {
 						newHostData = append(newHostData, vv)
 					}
@@ -300,14 +465,14 @@ cntfor:
 				v = nil
 				continue cntfor
 			}
-			if len(v.Host) > 1 {
+			if len(v.host) > 1 {
 				var newHosts []string
-				for _, vv := range v.Host {
+				for _, vv := range v.host {
 					if vv != host {
 						newHosts = append(newHosts, vv)
 					}
 				}
-				v.Host = newHosts
+				v.host = newHosts
 				var newHostData []*HostNode
 				for _, vv := range h.hostData[host] {
 					if vv.uid != v.uid {
@@ -338,14 +503,14 @@ func (h *Host) RemoveIPs(ips ...string) error {
 			if v.lastuid != 0 {
 				h.fulldata[v.lastuid].nextuid = v.nextuid
 			} else {
-				h.nextUid = v.nextuid
+				h.firstUid = v.nextuid
 			}
 			if v.nextuid != 0 {
 				h.fulldata[v.nextuid].lastuid = v.lastuid
 			} else {
 				h.lastUid = v.lastuid
 			}
-			for _, host := range v.Host {
+			for _, host := range v.host {
 				var newHostData []*HostNode
 				for _, vv := range h.hostData[host] {
 					if vv.uid != v.uid {
@@ -373,18 +538,18 @@ func (h *Host) RemoveHosts(hosts ...string) error {
 		delete(h.hostData, host)
 		for _, v := range hostInfo {
 			var newHosts []string
-			for _, vv := range v.Host {
+			for _, vv := range v.host {
 				if vv != host {
 					newHosts = append(newHosts, vv)
 				}
 			}
-			v.Host = newHosts
-			if len(v.Host) == 0 {
-				delete(h.ipData, v.IP)
+			v.host = newHosts
+			if len(v.host) == 0 {
+				delete(h.ipData, v.ip)
 				if v.lastuid != 0 {
 					h.fulldata[v.lastuid].nextuid = v.nextuid
 				} else {
-					h.nextUid = v.nextuid
+					h.firstUid = v.nextuid
 				}
 				if v.nextuid != 0 {
 					h.fulldata[v.nextuid].lastuid = v.lastuid
@@ -399,6 +564,14 @@ func (h *Host) RemoveHosts(hosts ...string) error {
 }
 
 func (h *Host) SetIPHosts(ip string, hosts ...string) error {
+	info := h.ListByIP(ip)
+	if len(info) == 0 {
+		return h.AddHosts(ip, hosts...)
+	} else if len(info) == 1 {
+		info[0].host = hosts
+		info[0].comment = ""
+		return nil
+	}
 	err := h.RemoveIPs(ip)
 	if err != nil {
 		return err
@@ -406,6 +579,22 @@ func (h *Host) SetIPHosts(ip string, hosts ...string) error {
 	return h.AddHosts(ip, hosts...)
 }
 
+func (h *Host) SetHostIPs(host string, ips ...string) error {
+	info := h.ListByHost(host)
+	if len(info) == 0 {
+		return h.AddHosts(host, ips...)
+	} else if len(info) == 1 {
+		info[0].ip = ips[0]
+		info[0].comment = ""
+		return nil
+	}
+	err := h.RemoveHosts(host)
+	if err != nil {
+		return err
+	}
+	return h.AddHosts(ips[0], host)
+}
+
 func (h *Host) addHosts(comment string, ip string, hosts ...string) error {
 	h.Lock()
 	defer h.Unlock()
@@ -422,14 +611,17 @@ func (h *Host) addHosts(comment string, ip string, hosts ...string) error {
 	if len(needAddHosts) == 0 {
 		return nil
 	}
+	if comment != "" && !strings.HasPrefix(strings.TrimSpace(comment), "#") {
+		comment = "#" + comment
+	}
 	hostNode := HostNode{
 		uid:     h.idx + 1,
 		nextuid: 0,
 		lastuid: h.lastUid,
-		IP:      ip,
-		Host:    needAddHosts,
-		Valid:   true,
-		Comment: comment,
+		ip:      ip,
+		host:    needAddHosts,
+		valid:   true,
+		comment: comment,
 	}
 	h.idx++
 	h.fulldata[h.lastUid].nextuid = h.idx
@@ -442,7 +634,7 @@ func (h *Host) addHosts(comment string, ip string, hosts ...string) error {
 	return nil
 }
 
-func (h *Host) InsertNodes(node *HostNode, before bool, comment string, ip string, hosts ...string) error {
+func (h *Host) InsertNodeByData(node *HostNode, before bool, comment string, ip string, hosts ...string) error {
 	h.Lock()
 	defer h.Unlock()
 	if h.hostData == nil {
@@ -451,15 +643,18 @@ func (h *Host) InsertNodes(node *HostNode, before bool, comment string, ip strin
 	if _, ok := h.fulldata[node.uid]; !ok {
 		return fmt.Errorf("node not exists")
 	}
+	if comment != "" && !strings.HasPrefix(strings.TrimSpace(comment), "#") {
+		comment = "#" + comment
+	}
 	hostNode := HostNode{
 		uid:     h.idx + 1,
-		IP:      ip,
-		Host:    hosts,
-		Valid:   true,
-		Comment: comment,
+		ip:      ip,
+		host:    hosts,
+		valid:   true,
+		comment: comment,
 	}
 	if ip == "" && len(hosts) == 0 && comment != "" {
-		hostNode.OnlyComment = true
+		hostNode.onlyComment = true
 	}
 	if before {
 		hostNode.nextuid = node.uid
@@ -467,7 +662,7 @@ func (h *Host) InsertNodes(node *HostNode, before bool, comment string, ip strin
 		if node.lastuid != 0 {
 			h.fulldata[node.lastuid].nextuid = h.idx
 		} else {
-			h.nextUid = h.idx
+			h.firstUid = h.idx
 		}
 		node.lastuid = h.idx
 	} else {
@@ -483,6 +678,119 @@ func (h *Host) InsertNodes(node *HostNode, before bool, comment string, ip strin
 	return nil
 }
 
+func (h *Host) DeleteNode(node *HostNode) error {
+	h.Lock()
+	defer h.Unlock()
+	if h.hostData == nil {
+		return fmt.Errorf("hosts data not initialized")
+	}
+	if _, ok := h.fulldata[node.uid]; !ok {
+		return fmt.Errorf("node not exists")
+	}
+	if node.lastuid != 0 {
+		h.fulldata[node.lastuid].nextuid = node.nextuid
+	} else {
+		h.firstUid = node.nextuid
+	}
+	if node.nextuid != 0 {
+		h.fulldata[node.nextuid].lastuid = node.lastuid
+	} else {
+		h.lastUid = node.lastuid
+	}
+	for _, v := range node.host {
+		var newHostData []*HostNode
+		for _, vv := range h.hostData[v] {
+			if vv.uid != node.uid {
+				newHostData = append(newHostData, vv)
+			}
+		}
+		h.hostData[v] = newHostData
+	}
+	ipInfo := h.ipData[node.ip]
+	var newIPData []*HostNode
+	for _, v := range ipInfo {
+		if v.uid != node.uid {
+			newIPData = append(newIPData, v)
+		}
+	}
+	h.ipData[node.ip] = newIPData
+	delete(h.fulldata, node.uid)
+	return nil
+}
+
+func (h *Host) DeleteNodeByUID(uid uint64) error {
+	h.RLock()
+	node, ok := h.fulldata[uid]
+	if !ok {
+		h.RUnlock()
+		return fmt.Errorf("node not exists")
+	}
+	h.RUnlock()
+	return h.DeleteNode(node)
+}
+
+func (h *Host) AddNode(node *HostNode) error {
+	h.Lock()
+	defer h.Unlock()
+	if h.hostData == nil {
+		return fmt.Errorf("hosts data not initialized")
+	}
+	if node.comment != "" && !strings.HasPrefix(strings.TrimSpace(node.comment), "#") {
+		node.comment = "#" + node.comment
+	}
+	if node.ip == "" && len(node.host) == 0 && node.comment != "" {
+		node.onlyComment = true
+	}
+	h.idx++
+	node.uid = h.idx
+	node.lastuid = h.lastUid
+	node.nextuid = 0
+	h.fulldata[h.lastUid].nextuid = node.uid
+	h.lastUid = node.uid
+	h.fulldata[node.uid] = node
+	node.valid = node.CheckValid()
+	if node.valid {
+		h.ipData[node.ip] = append(h.ipData[node.ip], node)
+		for _, v := range node.host {
+			h.hostData[v] = append(h.hostData[v], node)
+		}
+	}
+	return nil
+}
+
+func (h *Host) InsertNode(node *HostNode) error {
+	if node.lastuid == 0 && node.nextuid == 0 {
+		return h.AddNode(node)
+	}
+	h.Lock()
+	defer h.Unlock()
+	if h.hostData == nil {
+		return fmt.Errorf("hosts data not initialized")
+	}
+	if node.comment != "" && !strings.HasPrefix(strings.TrimSpace(node.comment), "#") {
+		node.comment = "#" + node.comment
+	}
+	if node.ip == "" && len(node.host) == 0 && node.comment != "" {
+		node.onlyComment = true
+	}
+	node.uid = h.idx + 1
+	if h.fulldata[node.lastuid].nextuid != node.nextuid {
+		return fmt.Errorf("node lastuid nextuid not match")
+	}
+	h.idx++
+	h.fulldata[node.lastuid].nextuid = node.uid
+	h.fulldata[node.nextuid].lastuid = node.uid
+	h.fulldata[node.uid] = node
+	node.valid = node.CheckValid()
+	if node.valid {
+		h.ipData[node.ip] = append(h.ipData[node.ip], node)
+		for _, v := range node.host {
+			h.hostData[v] = append(h.hostData[v], node)
+		}
+	}
+	return nil
+}
+
 func inArray(arr []string, v string) bool {
 	for _, vv := range arr {
 		if v == vv {
@@ -493,75 +801,325 @@ func inArray(arr []string, v string) bool {
 }
 
 func (h *Host) SaveAs(path string) error {
-	h.Lock()
-	defer h.Unlock()
 	return h.save(path)
 }
 
 func (h *Host) Save() error {
-	h.Lock()
-	defer h.Unlock()
 	return h.save(h.hostPath)
 }
 
 func (h *Host) save(path string) error {
 	h.Lock()
 	defer h.Unlock()
+	if h.firstUid == 0 || h.fulldata == nil {
+		return fmt.Errorf("no data")
+	}
 	f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
 	if err != nil {
 		return fmt.Errorf("open hosts file %s error: %s", h.hostPath, err)
 	}
 	defer f.Close()
-	for _, v := range h.fulldata {
-		if v.OnlyComment {
-			if _, err := f.WriteString(v.Comment + "\n"); err != nil {
+	node := h.fulldata[h.firstUid]
+	if node == nil {
+		return fmt.Errorf("no data")
+	}
+	for {
+		if node.onlyComment {
+			if _, err := f.WriteString(node.comment + "\n"); err != nil {
 				return fmt.Errorf("write hosts file error: %s", err)
 			}
+			if node.nextuid == 0 {
+				break
+			}
+			node = h.fulldata[node.nextuid]
 			continue
 		}
-		if _, err := f.WriteString(v.IP + " "); err != nil {
+		if _, err := f.WriteString(node.ip + " "); err != nil {
 			return fmt.Errorf("write hosts file error: %s", err)
 		}
-		if _, err := f.WriteString(strings.Join(v.Host, " ")); err != nil {
+		if _, err := f.WriteString(strings.Join(node.host, " ")); err != nil {
 			return fmt.Errorf("write hosts file error: %s", err)
 		}
-		if len(v.Comment) > 0 {
-			if _, err := f.WriteString(" " + v.Comment); err != nil {
+		if len(node.comment) > 0 {
+			if _, err := f.WriteString(" " + node.comment); err != nil {
 				return fmt.Errorf("write hosts file error: %s", err)
 			}
 		}
 		if _, err := f.WriteString(lineBreaker); err != nil {
 			return fmt.Errorf("write hosts file error: %s", err)
 		}
+		if node.nextuid == 0 {
+			break
+		}
+		node = h.fulldata[node.nextuid]
 	}
 	return nil
 }
 
 func (h *Host) Build() ([]byte, error) {
+	if h.firstUid == 0 || h.fulldata == nil {
+		return nil, fmt.Errorf("no data")
+	}
 	h.Lock()
 	defer h.Unlock()
 	var f bytes.Buffer
-	for _, v := range h.fulldata {
-		if v.OnlyComment {
-			if _, err := f.WriteString(v.Comment + "\n"); err != nil {
+	node := h.fulldata[h.firstUid]
+	if node == nil {
+		return nil, fmt.Errorf("no data")
+	}
+	for {
+		if node.onlyComment {
+			if _, err := f.WriteString(node.comment + "\n"); err != nil {
 				return nil, fmt.Errorf("write hosts file error: %s", err)
 			}
+			if node.nextuid == 0 {
+				break
+			}
+			node = h.fulldata[node.nextuid]
 			continue
 		}
-		if _, err := f.WriteString(v.IP + " "); err != nil {
+		if _, err := f.WriteString(node.ip + " "); err != nil {
 			return nil, fmt.Errorf("write hosts file error: %s", err)
 		}
-		if _, err := f.WriteString(strings.Join(v.Host, " ")); err != nil {
+		if _, err := f.WriteString(strings.Join(node.host, " ")); err != nil {
 			return nil, fmt.Errorf("write hosts file error: %s", err)
 		}
-		if len(v.Comment) > 0 {
-			if _, err := f.WriteString(" " + v.Comment); err != nil {
+		if len(node.comment) > 0 {
+			if _, err := f.WriteString(" " + node.comment); err != nil {
 				return nil, fmt.Errorf("write hosts file error: %s", err)
 			}
 		}
 		if _, err := f.WriteString(lineBreaker); err != nil {
 			return nil, fmt.Errorf("write hosts file error: %s", err)
 		}
+		if node.nextuid == 0 {
+			break
+		}
+		node = h.fulldata[node.nextuid]
 	}
 	return f.Bytes(), nil
 }
+
+func (h *Host) GetFirstNode() (*HostNode, error) {
+	h.RLock()
+	defer h.RUnlock()
+	if h.firstUid == 0 {
+		return nil, fmt.Errorf("no data")
+	}
+	if h.fulldata == nil {
+		return nil, fmt.Errorf("no data")
+	}
+	return h.fulldata[h.firstUid], nil
+}
+
+func (h *Host) GetNode(nodeID uint64) (*HostNode, error) {
+	h.RLock()
+	defer h.RUnlock()
+	if h.fulldata == nil {
+		return nil, fmt.Errorf("no data")
+	}
+	if node, ok := h.fulldata[nodeID]; ok {
+		return node, nil
+	}
+	return nil, fmt.Errorf("node not exists")
+}
+
+func (h *Host) GetNextNode(nodeID uint64) (*HostNode, error) {
+	h.RLock()
+	defer h.RUnlock()
+	if h.fulldata == nil {
+		return nil, fmt.Errorf("no data")
+	}
+	if node, ok := h.fulldata[nodeID]; ok {
+		if node.nextuid == 0 {
+			return nil, fmt.Errorf("no next node")
+		}
+		return h.fulldata[node.nextuid], nil
+	}
+	return nil, fmt.Errorf("node not exists")
+}
+
+func (h *Host) GetLastNode(nodeID uint64) (*HostNode, error) {
+	h.RLock()
+	defer h.RUnlock()
+	if h.fulldata == nil {
+		return nil, fmt.Errorf("no data")
+	}
+	if node, ok := h.fulldata[nodeID]; ok {
+		if node.lastuid == 0 {
+			return nil, fmt.Errorf("no last node")
+		}
+		return h.fulldata[node.lastuid], nil
+	}
+	return nil, fmt.Errorf("node not exists")
+}
+
+func (h *Host) GetLatestNode() (*HostNode, error) {
+	h.RLock()
+	defer h.RUnlock()
+	if h.lastUid == 0 {
+		return nil, fmt.Errorf("no data")
+	}
+	if h.fulldata == nil {
+		return nil, fmt.Errorf("no data")
+	}
+	return h.fulldata[h.lastUid], nil
+}
+
+func (h *Host) UpdateNode(node *HostNode) error {
+	h.Lock()
+	defer h.Unlock()
+	if h.fulldata == nil {
+		return fmt.Errorf("no data")
+	}
+	if _, ok := h.fulldata[node.uid]; !ok {
+		return fmt.Errorf("node not exists")
+	}
+	if node.comment != "" && !strings.HasPrefix(strings.TrimSpace(node.comment), "#") {
+		node.comment = "#" + node.comment
+	}
+	if node.ip == "" && len(node.host) == 0 && node.comment != "" {
+		node.onlyComment = true
+	}
+	h.fulldata[node.uid] = node
+	node.valid = node.CheckValid()
+	for k, v := range h.ipData {
+		var newIPData []*HostNode
+		for _, vv := range v {
+			if vv.uid != node.uid {
+				newIPData = append(newIPData, vv)
+			}
+		}
+		h.ipData[k] = newIPData
+	}
+	for k, v := range h.hostData {
+		var newHostData []*HostNode
+		for _, vv := range v {
+			if vv.uid != node.uid {
+				newHostData = append(newHostData, vv)
+			}
+		}
+		h.hostData[k] = newHostData
+	}
+	if node.valid {
+		h.ipData[node.ip] = append(h.ipData[node.ip], node)
+		for _, v := range node.host {
+			h.hostData[v] = append(h.hostData[v], node)
+		}
+	}
+	return nil
+}
+
+func (n *HostNode) String() string {
+	if n.onlyComment {
+		return n.comment
+	}
+	return fmt.Sprintf("%s %s %s", n.ip, strings.Join(n.host, " "), n.comment)
+}
+
+func (n *HostNode) Bytes() []byte {
+	return []byte(n.String())
+}
+
+func (n *HostNode) Hosts() []string {
+	return n.host
+}
+
+func (n *HostNode) IP() string {
+	return n.ip
+}
+
+func (n *HostNode) Comment() string {
+	return n.comment
+}
+
+func (n *HostNode) UID() uint64 {
+	return n.uid
+}
+
+func (n *HostNode) NextUID() uint64 {
+	return n.nextuid
+}
+
+func (n *HostNode) LastUID() uint64 {
+	return n.lastuid
+}
+
+func (n *HostNode) Valid() bool {
+	return n.valid
+}
+
+func (n *HostNode) OnlyComment() bool {
+	return n.onlyComment
+}
+
+func (n *HostNode) Original() string {
+	return n.original
+}
+
+func (n *HostNode) SetHosts(hosts ...string) {
+	n.host = hosts
+}
+
+func (n *HostNode) SetIP(ip string) {
+	n.ip = ip
+}
+
+func (n *HostNode) SetComment(comment string) {
+	if comment == "" {
+		return
+	}
+	if !strings.HasPrefix(strings.TrimSpace(comment), "#") {
+		n.comment = "#" + comment
+		return
+	}
+	n.comment = comment
+}
+
+func (n *HostNode) SetValid(valid bool) {
+	n.valid = valid
+}
+
+func (n *HostNode) SetOnlyComment(onlyComment bool) {
+	n.onlyComment = onlyComment
+}
+
+func (n *HostNode) SetOriginal(original string) {
+	n.original = original
+}
+
+func (n *HostNode) AddHosts(hosts ...string) {
+	n.host = append(n.host, hosts...)
+}
+
+func (n *HostNode) SetLastUID(uid uint64) error {
+	if n.uid != 0 {
+		return fmt.Errorf("uid already set,you cannot change the existing node")
+	}
+	n.lastuid = uid
+	return nil
+}
+
+func (n *HostNode) SetNextUID(uid uint64) error {
+	if n.uid != 0 {
+		return fmt.Errorf("uid already set,you cannot change the existing node")
+	}
+	n.nextuid = uid
+	return nil
+}
+
+func (n *HostNode) CheckValid() bool {
+	if n.ip == "" && len(n.host) == 0 && n.comment == "" {
+		return true
+	}
+	if n.ip == "" && len(n.host) == 0 && n.comment != "" {
+		return true
+	}
+	if n.ip == "" && len(n.host) > 0 {
+		return false
+	}
+	if net.ParseIP(n.ip) == nil {
+		return false
+	}
+	return true
+}
diff --git a/hosts/hosts_test.go b/hosts/hosts_test.go
index 80f1e2b..8ae2394 100644
--- a/hosts/hosts_test.go
+++ b/hosts/hosts_test.go
@@ -11,27 +11,127 @@ func Test_Hosts(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	for _, v := range h.List() {
-		fmt.Printf("%+v\n", v)
+	next := h.firstUid
+	for next != 0 {
+		node, _ := h.GetNode(next)
+		fmt.Printf("Last %d, Next: %d, IP: %s, Hosts: %s, Comment: %s\n", node.LastUID(), node.NextUID(), node.IP(), node.Hosts(), node.Comment())
+		next = node.NextUID()
 	}
-	fmt.Println(h.nextUid, h.lastUid)
-	fmt.Println("")
-	err = h.AddHosts("122.23.12.123", "b612.me", "ok.b612.me")
+	data := h.ListHostsByIP("11.22.33.44")
+	if len(data) != 2 {
+		t.Error("Expected 2, got ", len(data))
+	} else {
+		t.Log(data)
+	}
+
+	data = h.ListIPsByHost("dns.b612.me")
+	if len(data) < 1 || data[0] != "4.5.6.7" {
+		t.Error("Expected 4.5.6.7, got ", data)
+	} else {
+		t.Log(data)
+	}
+
+	err = h.RemoveHosts("dns.b612.me")
+	if err != nil {
+		t.Error(err)
+	}
+	data = h.ListIPsByHost("dns.b612.me")
+	if len(data) > 0 {
+		t.Error("Expected 0, got ", len(data))
+	} else {
+		t.Log(data)
+	}
+
+	err = h.RemoveHosts("test.dns.set.b612.me")
+	if err != nil {
+		t.Error(err)
+	}
+
+	data = h.ListIPsByHost("remove.b612.me")
+	if len(data) < 1 || data[0] != "11.22.33.44" {
+		t.Error("Expected 11.22.33.44, got ", data)
+	} else {
+		t.Log(data)
+	}
+
+	nodes := h.ListByIP("11.22.33.44")
+	if nodes == nil {
+		t.Error("Expected not nil, got ", nodes)
+	} else {
+		t.Log(nodes)
+	}
+
+	nodes[0].AddHosts("hello.b612.me")
+	err = h.UpdateNode(nodes[0])
 	if err != nil {
 		t.Error(err)
 	}
-	for _, v := range h.List() {
-		fmt.Printf("%+v\n", v)
+	data = h.ListIPsByHost("hello.b612.me")
+	if len(data) < 1 || data[0] != "11.22.33.44" {
+		t.Error("Not Expected Data", data)
+	} else {
+		t.Log(data)
 	}
-	fmt.Println(h.nextUid, h.lastUid)
-	fmt.Println("")
-	err = h.RemoveIPHosts("11.22.33.44", "remove.b612.me", "test.dns.set.b612.me")
+	insertNode := new(HostNode)
+	insertNode.SetIP("11.11.11.11")
+	insertNode.SetHosts("insert.b612.me")
+	insertNode.SetComment("Insert Node")
+	insertNode.SetNextUID(nodes[0].UID())
+	insertNode.SetLastUID(nodes[0].LastUID())
+	err = h.InsertNode(insertNode)
 	if err != nil {
 		t.Error(err)
 	}
-	for _, v := range h.List() {
-		fmt.Printf("%+v\n", v)
+	data = h.ListIPsByHost("insert.b612.me")
+	if len(data) < 1 || data[0] != "11.11.11.11" {
+		t.Error("Expected 11.11.11.11 got ", data)
+	} else {
+		t.Log(data)
+	}
+
+	err = h.SaveAs("./test_hosts_01.txt")
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = h.DeleteNode(insertNode)
+	if err != nil {
+		t.Error(err)
+	}
+	data = h.ListIPsByHost("insert.b612.me")
+	if len(data) > 0 {
+		t.Error("Expected 0 got ", data)
+	} else {
+		t.Log(data)
+	}
+
+	for i := 0; i < 100; i++ {
+		err = h.RemoveHosts("release-ftpd")
+		if err != nil {
+			t.Error(err)
+		}
+		err = h.AddHosts("2.3.4.9", "release-ftpd")
+		if err != nil {
+			t.Error(err)
+		}
+	}
+
+	err = h.SaveAs("./test_hosts_02.txt")
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func BenchmarkAddHosts(b *testing.B) {
+	var h = NewHosts()
+	err := h.Parse("./test_hosts.txt")
+	if err != nil {
+		b.Error(err)
+	}
+	for i := 0; i < b.N; i++ {
+		err = h.AddHosts("1.3.4.5", "test.b612.me")
+		if err != nil {
+			b.Error(err)
+		}
 	}
-	fmt.Println(h.nextUid, h.lastUid)
-	fmt.Println("")
 }
diff --git a/sysconf/sysconf_test.go b/sysconf/sysconf_test.go
index aa0e48c..76b589a 100644
--- a/sysconf/sysconf_test.go
+++ b/sysconf/sysconf_test.go
@@ -33,11 +33,10 @@ func Test_Parse(t *testing.T) {
 	fmt.Println(cfg.Parse([]byte(data)))
 	cfg.Reverse()
 	cfg.Data[0].Delete(`pp.com`)
-	//fmt.Println(cfg.Data[0].Comment)
+	//fmt.Println(cfg.Data[0].comment)
 	fmt.Println(string(cfg.Build()))
 }
 
-
 type slicetest struct {
 	A string `seg:"s" key:"a"`
 	B string `seg:"a" key:"b"`
@@ -50,7 +49,7 @@ type testme struct {
 
 func Test_Marshal(t *testing.T) {
 
-	var info string =`
+	var info string = `
 [love]
 a=abc
 b=123
@@ -59,10 +58,10 @@ a=456
 b=789
 `
 	var tmp testme
-	ini:=NewIni()
+	ini := NewIni()
 	ini.Parse([]byte(info))
 	ini.Unmarshal(&tmp)
-	fmt.Printf("%+v\n",tmp)
-	b,_:=ini.Marshal(tmp)
+	fmt.Printf("%+v\n", tmp)
+	b, _ := ini.Marshal(tmp)
 	fmt.Println(string(b))
-}
\ No newline at end of file
+}