diff --git a/.gitignore b/.gitignore
index 66fd13c..43b5f52 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,5 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+
+test
\ No newline at end of file
diff --git a/README.md b/README.md
index 0a881b2..802a1fd 100644
--- a/README.md
+++ b/README.md
@@ -51,4 +51,33 @@ func TestAPI(t *testing.T) {
 - ついなちゃん標準語
 - ついなちゃん関西弁
 - 伊織弓鶴
-- 音街ウナ
\ No newline at end of file
+- 音街ウナ
+
+## commandline tool
+```bash
+go run cmd/main.go -h
+Usage:
+  -a float
+        anger
+  -b uint
+        border slience sample lenth (default 2048)
+  -d float
+        sadness
+  -f string
+        line-separated text to read
+  -h    display this help
+  -j float
+        joy
+  -n string
+        specify speaker (default "民安ともえ")
+  -o string
+        output wav file path (default "out.wav")
+  -p float
+        pitch (default 1)
+  -r float
+        range (default 1)
+  -s float
+        speed (default 1)
+  -v float
+        volume (default 1)
+```
\ No newline at end of file
diff --git a/api.go b/api.go
index da0cc36..5badbbb 100644
--- a/api.go
+++ b/api.go
@@ -1,3 +1,4 @@
+// Package ahsai AH Soft フリーテキスト音声合成 demo API
 package ahsai
 
 import (
@@ -35,11 +36,14 @@ var (
 	}
 )
 
+// Speaker is a particular setting of the API
 type Speaker struct {
 	id                                               uint32
 	Volume, Speed, Pitch, Range, Anger, Sadness, Joy float32
 }
 
+// NewSpeaker init default para of a speaker.
+// Use s.SetName() to set the real speaker.
 func NewSpeaker() (s Speaker) {
 	s.Volume = 1
 	s.Speed = 1
@@ -55,6 +59,7 @@ var (
 	ErrNoSuchSpeaker = errors.New("no such speaker")
 )
 
+// SetName set the speaker id.
 func (s *Speaker) SetName(name string) error {
 	id, ok := speakers[name]
 	if !ok {
diff --git a/cmd/main.go b/cmd/main.go
new file mode 100644
index 0000000..649d30b
--- /dev/null
+++ b/cmd/main.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+
+	"github.com/faiface/beep/wav"
+	"github.com/fumiama/ahsai"
+)
+
+func main() {
+	f := flag.String("f", "", "line-separated text to read")
+	o := flag.String("o", "out.wav", "output wav file path")
+	n := flag.String("n", "民安ともえ", "specify speaker")
+	v := flag.Float64("v", 1.0, "volume")
+	s := flag.Float64("s", 1.0, "speed")
+	p := flag.Float64("p", 1.0, "pitch")
+	r := flag.Float64("r", 1.0, "range")
+	a := flag.Float64("a", 0, "anger")
+	d := flag.Float64("d", 0, "sadness")
+	j := flag.Float64("j", 0, "joy")
+	b := flag.Uint("b", 2048, "border slience sample lenth")
+	h := flag.Bool("h", false, "display this help")
+	flag.Parse()
+	if *h {
+		flag.Usage()
+		return
+	}
+	if *f == "" {
+		panic("parameter -f must be specified")
+	}
+	spk := ahsai.Speaker{Volume: float32(*v), Speed: float32(*s), Pitch: float32(*p), Range: float32(*r), Anger: float32(*a), Sadness: float32(*d), Joy: float32(*j)}
+	err := spk.SetName(*n)
+	if err != nil {
+		panic(err)
+	}
+	txt, err := os.Open(*f)
+	if err != nil {
+		panic(err)
+	}
+	sc := bufio.NewScanner(txt)
+	lst := make([]string, 0, 128)
+	i := 0
+	for sc.Scan() {
+		t := sc.Text()
+		i++
+		if len([]rune(t)) > 100 {
+			panic("line " + strconv.Itoa(i) + ": too long (> 100 chars)")
+		}
+		lst = append(lst, t)
+	}
+	err = txt.Close()
+	if err != nil {
+		panic(err)
+	}
+	for i, t := range lst {
+		u, err := spk.Speak(t)
+		if err != nil {
+			panic("line " + strconv.Itoa(i) + "error: " + err.Error())
+		}
+		lst[i] = u
+		fmt.Print("\rread: ", (i+1)*100/len(lst), " %")
+	}
+	sm, format, err := ahsai.ComposeStream(*b, func(p int) { fmt.Print("\rcompose: ", p, " %") }, lst...)
+	if err != nil {
+		panic(err)
+	}
+	out, err := os.Create(*o)
+	if err != nil {
+		panic(err)
+	}
+	defer out.Close()
+	err = wav.Encode(out, sm, format)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println("\rall process succeed")
+}
diff --git a/ogg.go b/ogg.go
index cc10cf3..03735ea 100644
--- a/ogg.go
+++ b/ogg.go
@@ -30,6 +30,37 @@ func cutstream(s beep.StreamSeekCloser) {
 	}
 }
 
+// ComposeStream 组合 urls 成为单个 stream, 并留出 sil 采样间隔
+func ComposeStream(sil uint, progress func(p int), urls ...string) (sm beep.Streamer, format beep.Format, err error) {
+	var buf *beep.Buffer
+	for i, u := range urls {
+		var resp *http.Response
+		resp, err = http.Get(u)
+		if err != nil {
+			return
+		}
+		var s beep.StreamSeekCloser
+		s, format, err = vorbis.Decode(resp.Body)
+		if err != nil {
+			_ = resp.Body.Close()
+			return
+		}
+		if i == 0 {
+			buf = beep.NewBuffer(format)
+		}
+		cutstream(s)
+		buf.Append(beep.Silence(int(sil)))
+		buf.Append(s)
+		_ = s.Close()
+		if progress != nil {
+			progress((i + 1) * 100 / len(urls))
+		}
+	}
+	sm = buf.Streamer(0, buf.Len())
+	return
+}
+
+// SaveOggToFile cut leading demo text and save wav to path
 func SaveOggToFile(u, path string) error {
 	resp, err := http.Get(u)
 	if err != nil {
@@ -37,7 +68,7 @@ func SaveOggToFile(u, path string) error {
 	}
 	s, format, err := vorbis.Decode(resp.Body)
 	if err != nil {
-		resp.Body.Close()
+		_ = resp.Body.Close()
 		return err
 	}
 	defer s.Close()
@@ -50,6 +81,7 @@ func SaveOggToFile(u, path string) error {
 	return wav.Encode(f, s, format)
 }
 
+// SaveOggToWriteSeeker cut leading demo text and write wav stream to f
 func SaveOggToWriteSeeker(u string, f io.WriteSeeker) error {
 	resp, err := http.Get(u)
 	if err != nil {
@@ -57,7 +89,7 @@ func SaveOggToWriteSeeker(u string, f io.WriteSeeker) error {
 	}
 	s, format, err := vorbis.Decode(resp.Body)
 	if err != nil {
-		resp.Body.Close()
+		_ = resp.Body.Close()
 		return err
 	}
 	defer s.Close()
@@ -65,6 +97,7 @@ func SaveOggToWriteSeeker(u string, f io.WriteSeeker) error {
 	return wav.Encode(f, s, format)
 }
 
+// PlayOgg cut leading demo text and play directly
 func PlayOgg(u string) error {
 	resp, err := http.Get(u)
 	if err != nil {
@@ -72,7 +105,7 @@ func PlayOgg(u string) error {
 	}
 	s, format, err := vorbis.Decode(resp.Body)
 	if err != nil {
-		resp.Body.Close()
+		_ = resp.Body.Close()
 		return err
 	}
 	defer s.Close()