diff --git a/obfssh_scp/scp.go b/obfssh_scp/scp.go
index fb35bb8..62cf0a8 100644
--- a/obfssh_scp/scp.go
+++ b/obfssh_scp/scp.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"github.com/bgentry/speakeasy"
@@ -20,28 +21,34 @@ import (
 	"time"
 )
 
-func main() {
-	var user, port, pass, key string
-	var recursive bool
-	var obfsMethod, obfsKey string
-	var disableObfsAfterHandshake bool
-	var debug bool
-	var hasError bool
+type options struct {
+	Debug                     bool
+	Port                      int
+	User                      string
+	Passwd                    string
+	Recursive                 bool
+	ObfsMethod                string
+	ObfsKey                   string
+	DisableObfsAfterHandshake bool
+	PrivateKey                string
+}
 
+func main() {
+	var cfg options
 	flag.Usage = usage
 
-	flag.BoolVar(&debug, "d", false, "verbose mode")
-	flag.StringVar(&port, "p", "22", "port")
-	flag.StringVar(&user, "l", os.Getenv("USER"), "user")
-	flag.StringVar(&pass, "pw", "", "password")
-	flag.StringVar(&key, "i", "", "private key")
-	flag.BoolVar(&recursive, "r", false, "recursively copy entries")
-	flag.StringVar(&obfsMethod, "obfs_method", "none", "obfs encrypt method, rc4, aes or none")
-	flag.StringVar(&obfsKey, "obfs_key", "", "obfs encrypt key")
-	flag.BoolVar(&disableObfsAfterHandshake, "disable_obfs_after_handshake", false, "disable obfs after handshake")
+	flag.BoolVar(&cfg.Debug, "d", false, "verbose mode")
+	flag.IntVar(&cfg.Port, "p", 22, "port")
+	flag.StringVar(&cfg.User, "l", os.Getenv("USER"), "user")
+	flag.StringVar(&cfg.Passwd, "pw", "", "password")
+	flag.StringVar(&cfg.PrivateKey, "i", "", "private key")
+	flag.BoolVar(&cfg.Recursive, "r", false, "recursively copy entries")
+	flag.StringVar(&cfg.ObfsMethod, "obfs_method", "none", "obfs encrypt method, rc4, aes or none")
+	flag.StringVar(&cfg.ObfsKey, "obfs_key", "", "obfs encrypt key")
+	flag.BoolVar(&cfg.DisableObfsAfterHandshake, "disable_obfs_after_handshake", false, "disable obfs after handshake")
 	flag.Parse()
 
-	if debug {
+	if cfg.Debug {
 		obfssh.SSHLogLevel = obfssh.DEBUG
 	}
 
@@ -52,35 +59,24 @@ func main() {
 		os.Exit(1)
 	}
 
-	var host, path string
-	r1 := ""
-	var toLocal = false
+	var err error
+
 	if strings.Contains(args[0], ":") {
-		toLocal = true
-		r1 = args[0]
+		err = download(args, &cfg)
 	} else {
-		toLocal = false
-		r1 = args[len(args)-1]
+		err = upload(args, &cfg)
 	}
 
-	if strings.Contains(r1, "@") {
-		ss1 := strings.SplitN(r1, "@", 2)
-		user = ss1[0]
-		r1 = ss1[1]
-	}
-	ss2 := strings.SplitN(r1, ":", 2)
-	if len(ss2) != 2 {
-		//log.Fatal("Usage: \n\tscp user@host:path local\n\tor\n\tscp local... user@host:path")
-		flag.Usage()
-		os.Exit(1)
+	if err != nil {
+		log.Fatal(err)
 	}
-	host = ss2[0]
-	path = ss2[1]
+}
 
+func createSFTPConn(host, user string, cfg *options) (*sftp.Client, error) {
 	auths := []ssh.AuthMethod{}
 
 	// read ssh agent and default auth key
-	if pass == "" && key == "" {
+	if cfg.Passwd == "" && cfg.PrivateKey == "" {
 		var pkeys []ssh.Signer
 		if aconn, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK")); err == nil {
 			//auths = append(auths, ssh.PublicKeysCallback(agent.NewClient(aconn).Signers))
@@ -121,19 +117,19 @@ func main() {
 		}
 	}
 
-	if pass != "" {
+	if cfg.Passwd != "" {
 		debuglog("add password auth")
-		auths = append(auths, ssh.Password(pass))
+		auths = append(auths, ssh.Password(cfg.Passwd))
 	} else {
 		debuglog("add keyboard interactive")
 		auths = append(auths,
 			ssh.RetryableAuthMethod(ssh.PasswordCallback(passwordAuth), 3))
 	}
 
-	if key != "" {
-		if buf, err := ioutil.ReadFile(key); err == nil {
+	if cfg.PrivateKey != "" {
+		if buf, err := ioutil.ReadFile(cfg.PrivateKey); err == nil {
 			if p, err := ssh.ParsePrivateKey(buf); err == nil {
-				debuglog("add private key: %s", key)
+				debuglog("add private key: %s", cfg.PrivateKey)
 				auths = append(auths, ssh.PublicKeys(p))
 			} else {
 				debuglog("parse private key failed: %s", err)
@@ -142,6 +138,9 @@ func main() {
 			debuglog("read private key failed: %s", err)
 		}
 	}
+	if user == "" {
+		user = cfg.User
+	}
 
 	config := &ssh.ClientConfig{
 		User:    user,
@@ -149,113 +148,189 @@ func main() {
 		Timeout: 5 * time.Second,
 	}
 
-	rhost := net.JoinHostPort(host, port)
+	rhost := net.JoinHostPort(host, fmt.Sprintf("%d", cfg.Port))
 
 	c, err := net.Dial("tcp", rhost)
 	if err != nil {
-		log.Fatal(err)
+		//log.Fatal(err)
+		return nil, err
 	}
 
 	conf := &obfssh.Conf{
-		ObfsMethod:                obfsMethod,
-		ObfsKey:                   obfsKey,
+		ObfsMethod:                cfg.ObfsMethod,
+		ObfsKey:                   cfg.ObfsKey,
 		Timeout:                   10 * time.Second,
 		KeepAliveInterval:         10 * time.Second,
 		KeepAliveMax:              5,
-		DisableObfsAfterHandshake: disableObfsAfterHandshake,
+		DisableObfsAfterHandshake: cfg.DisableObfsAfterHandshake,
 	}
 
 	conn, err := obfssh.NewClient(c, config, rhost, conf)
-
-	//conn, err := ssh.Dial("tcp", h, config)
 	if err != nil {
-		log.Fatal(err)
+		//log.Fatal(err)
+		return nil, err
 	}
 
-	defer conn.Close()
+	//defer conn.Close()
 
 	sftpConn, err := sftp.NewClient(conn.Client(), sftp.MaxPacket(64*1024))
 	if err != nil {
-		log.Fatal(err)
+		//log.Fatal(err)
+		return nil, err
 	}
-	defer sftpConn.Close()
+	return sftpConn, nil
+}
 
-	// download
-	if toLocal {
-		localFile := args[1]
-		st, err := sftpConn.Stat(path)
-		if err != nil {
-			log.Fatal(err)
-		}
+func splitHostPath(s string) (string, string, string) {
+	var user, host, path string
+	r1 := s
+	if strings.Contains(r1, "@") {
+		ss1 := strings.SplitN(r1, "@", 2)
+		user = ss1[0]
+		r1 = ss1[1]
+	}
+	if strings.Contains(r1, ":") {
+		ss2 := strings.SplitN(r1, ":", 2)
+		host = ss2[0]
+		path = ss2[1]
+	} else {
+		host = r1
+	}
+	return user, host, path
+}
+
+func download(args []string, cfg *options) error {
+
+	var err1 error
 
-		if st.Mode().IsDir() && !recursive {
-			log.Fatal("use -r to transfer the directory")
+	localFile := clean(args[len(args)-1])
+
+	st, _ := os.Stat(localFile)
+
+	if len(args) > 2 {
+		if st != nil && !st.Mode().IsDir() {
+			log.Fatal("can't transfer multiple files to file")
+		}
+		if st == nil {
+			makeDirs(localFile, osDir{})
+			if err := os.Mkdir(localFile, 0755); err != nil {
+				log.Fatal(err)
+			}
 		}
+		st, _ = os.Stat(localFile)
+	}
 
-		st1, err := os.Stat(localFile)
-		if err == nil && !st1.Mode().IsDir() && st.Mode().IsDir() {
-			log.Fatal("can't transfer directory to file")
+	for _, f := range args[:len(args)-1] {
+		user, host, path := splitHostPath(f)
+		if host == "" || path == "" {
+			return errors.New("invalid path")
 		}
 
-		if !st.Mode().IsDir() {
-			if st1 != nil && st1.Mode().IsDir() {
-				// to local directory
-				bname := filepath.Base(path)
-				localFile = filepath.Join(localFile, bname)
-			}
+		path = clean(path)
 
-			debuglog("transfer remote to local, %s -> %s", path, localFile)
+		sftpConn, err := createSFTPConn(host, user, cfg)
+		if err != nil {
+			return err
+		}
 
-			if err := get(sftpConn, path, localFile); err != nil {
-				log.Fatal(err)
+		st1, err := sftpConn.Stat(path)
+		if err != nil {
+			err1 = err
+			debuglog("%s", err)
+			sftpConn.Close()
+			continue
+		}
+		if st1.Mode().IsDir() {
+			if !cfg.Recursive {
+				debuglog("omit remote directory %s", path)
+				sftpConn.Close()
+				continue
 			}
-			debuglog("done")
-			return
+			if err := rget(sftpConn, path, localFile); err != nil {
+				debuglog("download error: %s", err)
+				err1 = err
+			}
+			sftpConn.Close()
+			continue
 		}
 
-		// recursive download
-		if err := rget(sftpConn, path, localFile); err != nil {
-			log.Fatal(err)
+		lfile := localFile
+		if st != nil && st.Mode().IsDir() {
+			lfile = filepath.Join(lfile, filepath.Base(path))
 		}
 
-		// download done
-		debuglog("done")
+		if err := get(sftpConn, path, lfile); err != nil {
+			debuglog("download error: %s", err)
+			err1 = err
+		}
 
-		return
+		sftpConn.Close()
 	}
 
-	// upload
+	debuglog("done")
+	return err1
+}
+
+func upload(args []string, cfg *options) error {
+
+	rfile := args[len(args)-1]
+
+	rfile = clean(rfile)
+
+	user, host, path := splitHostPath(rfile)
+
+	if host == "" || path == "" {
+		return errors.New("invalid path")
+	}
+
+	path = clean(path)
+
+	sftpConn, err := createSFTPConn(host, user, cfg)
+	if err != nil {
+		return err
+	}
+	defer sftpConn.Close()
+
+	st, _ := sftpConn.Stat(path)
+
+	var err1 error
 	if len(args) > 2 {
-		if st, err := sftpConn.Stat(path); err == nil {
-			if !st.Mode().IsDir() {
-				log.Fatal("multiple files can only been transferred to directory")
+		if st != nil && !st.Mode().IsDir() {
+			log.Fatal("multiple files can only been transferred to directory")
+		}
+		if st == nil {
+			makeDirs(path, sftpConn)
+			if err := sftpConn.Mkdir(path); err != nil {
+				log.Fatal(err)
 			}
-		} else {
-			log.Fatalf("remote file or directory not exists")
 		}
+		st, _ = sftpConn.Stat(path)
 	}
 
 	for i := 0; i < len(args)-1; i++ {
 		localFile := args[i]
-		st, err := os.Stat(localFile)
+
+		localFile = clean(localFile)
+
+		st1, err := os.Stat(localFile)
 
 		// local file not exists
 		if err != nil {
 			debuglog("%s", err)
-			hasError = true
+			err1 = err
 			continue
 		}
 
 		// directory
-		if st.Mode().IsDir() {
-			if !recursive {
+		if st1.Mode().IsDir() {
+			if !cfg.Recursive {
 				debuglog("omit directory %s", localFile)
 				continue
 			}
 			// transfer directory
 			if err := rput(sftpConn, localFile, path); err != nil {
 				debuglog("%s", err)
-				hasError = true
+				err1 = err
 			}
 
 			// next entry
@@ -266,21 +341,16 @@ func main() {
 
 		remoteFile := path
 
-		st1, err := sftpConn.Stat(path)
-		if err == nil && st1.Mode().IsDir() {
+		if st != nil && st.Mode().IsDir() {
 			remoteFile = filepath.Join(path, filepath.Base(localFile))
 		}
 
 		if err := put(sftpConn, localFile, remoteFile); err != nil {
-			hasError = true
 			debuglog("upload %s failed: %s", localFile, err.Error())
+			err1 = err
 		}
 	}
-
-	if hasError {
-		os.Exit(1)
-	}
-
+	return err1
 }
 
 func get(sftpConn *sftp.Client, remoteFile, localFile string) error {
@@ -382,13 +452,13 @@ func rput(sftpConn *sftp.Client, localDir, remoteDir string) error {
 			continue
 		}
 
-		p := walker.Path()
+		p := clean(walker.Path())
 
 		p1 := strings.Replace(p, localDir, "", 1)
 
 		fmt.Println(strings.TrimLeft(p1, "/"))
 
-		p2 := filepath.Join(remoteDir, p1)
+		p2 := clean(filepath.Join(remoteDir, p1))
 
 		if err := makeDirs(p2, sftpConn); err != nil {
 			return err
@@ -415,13 +485,13 @@ func rget(sftpConn *sftp.Client, remoteDir, localDir string) error {
 			continue
 		}
 
-		p := walker.Path()
+		p := clean(walker.Path())
 		p1 := strings.Replace(p, remoteDir, "", 1)
-		p2 := filepath.Join(localDir, p1)
+		p2 := clean(filepath.Join(localDir, p1))
 
 		fmt.Println(strings.TrimLeft(p1, "/"))
 
-		if err := makeDirs(p2, fi{}); err != nil {
+		if err := makeDirs(p2, osDir{}); err != nil {
 			return err
 		}
 
@@ -433,22 +503,24 @@ func rget(sftpConn *sftp.Client, remoteDir, localDir string) error {
 	return nil
 }
 
-type fi struct{}
+type osDir struct{}
 
-func (f fi) Stat(s string) (os.FileInfo, error) {
+func (f osDir) Stat(s string) (os.FileInfo, error) {
 	return os.Stat(s)
 }
 
-func (f fi) Mkdir(s string) error {
+func (f osDir) Mkdir(s string) error {
 	return os.Mkdir(s, 0755)
 }
 
-type fileInterface interface {
+type dirInterface interface {
 	Stat(s string) (os.FileInfo, error)
 	Mkdir(s string) error
 }
 
-func makeDirs(p string, c fileInterface) error {
+func makeDirs(p string, c dirInterface) error {
+	p = clean(p)
+
 	debuglog("make directory for %s", p)
 
 	for i := 1; i < len(p); i++ {
@@ -544,3 +616,11 @@ Options for obfuscation:
 	fmt.Printf("%s", usageStr)
 	os.Exit(1)
 }
+
+func clean(p string) string {
+	p = filepath.Clean(p)
+	if os.PathSeparator != '/' {
+		p = strings.Replace(p, string([]byte{os.PathSeparator}), "/", -1)
+	}
+	return p
+}