diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 0000000..72e38f0
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,19 @@
+{
+    // 使用 IntelliSense 了解相关属性。 
+    // 悬停以查看现有属性的描述。
+    // 欲了解更多信息，请访问: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${fileDirname}",
+            "args":[
+                "-a",
+                "ssd"
+            ]
+        }
+    ]
+}
\ No newline at end of file
diff --git a/command.go b/command.go
index c3ac782..54a8471 100644
--- a/command.go
+++ b/command.go
@@ -2,9 +2,12 @@ package command
 
 import (
 	"errors"
+	"fmt"
+	"os"
 	"reflect"
 	"strconv"
 	"strings"
+	"text/template"
 )
 
 type Option struct {
@@ -15,17 +18,48 @@ type Option struct {
 	OType        string
 	DefaultValue interface{}
 }
+
+var UsageTemplate, _ = template.New("Usage").Parse(`Usage:
+ {{if .ParentCommand }} {{.ParentCommand.Name}} {{end}} {{.Name}} [OPTIONS] [ARGS]
+{{ if .Description }}
+Description:
+  {{.Description}}
+{{ end }}
+{{ if .Args }}
+Options:
+  {{range .Args}}
+  -{{.ShortName}}|--{{.LongName}} {{.OType}} {{.Description}} default:{{.DefaultValue}}
+  {{end}}
+{{ end }}
+{{ if .SubCommands }}
+ Sub Commands:
+  {{range .SubCommands}}
+  {{.Name}} {{.Description}}
+  {{end}}
+{{end}}
+`)
+
 type Command struct {
 	Name              string
 	Description       string
 	Args              []*Option
 	SubCommands       []*Command
-	parentCommand     *Command
+	ParentCommand     *Command
 	subcommand        string
 	globalOptions     map[string]interface{}
 	subcommandOptions map[string]interface{}
+	remainArgs        []string
 }
 
+func (c *Command) GetGlobalOptions() map[string]interface{} {
+	return c.globalOptions
+}
+func (c *Command) GetSubCommandOptions() map[string]interface{} {
+	return c.subcommandOptions
+}
+func (c *Command) GetSubCommand() string {
+	return c.subcommand
+}
 func (c *Command) AddArg(name string, shortName string, description string, defaultValue interface{}) {
 	oType := reflect.TypeOf(defaultValue).String()
 	c.Args = append(c.Args, &Option{
@@ -39,19 +73,19 @@ func (c *Command) AddArg(name string, shortName string, description string, defa
 }
 
 func (c *Command) AddSubCommand(name string, description string) *Command {
-	if c.parentCommand != nil {
+	if c.ParentCommand != nil {
 		panic("Sub commands can only be added to top level commands")
 	}
 	command := &Command{
 		Name:          name,
 		Description:   description,
-		parentCommand: c,
+		ParentCommand: c,
 	}
 	c.SubCommands = append(c.SubCommands, command)
 	return command
 }
 func (c *Command) Usage() {
-	panic("not implemented")
+	UsageTemplate.Execute(os.Stdout, c)
 }
 func (c *Command) GetOption(name string) *Option {
 	if len(name) > 1 {
@@ -68,17 +102,91 @@ func (c *Command) GetOption(name string) *Option {
 	}
 	return nil
 }
-
-func (c *Command) parse(args []string) {
+func (c *Command) parseError(errMsg string) {
+	fmt.Println(errMsg)
+	os.Exit(1)
+}
+func (c *Command) showHelpWithOption(args []string) {
+	if len(args) > 0 && (args[0] == "-h" || args[0] == "--help") {
+		c.Usage()
+		os.Exit(0)
+	}
+}
+func (c *Command) showSubCommandHelp(args []string) {
+	if len(args) == 2 && args[0] == "help" {
+		cmd := c.findSubcommand(args[1])
+		if cmd == nil {
+			c.parseError("Unknown subcommand " + args[1])
+		}
+		cmd.Usage()
+		os.Exit(0)
+	}
+}
+func (c *Command) Parse(args []string) ([]string, error) {
+	c.showHelpWithOption(args)
+	c.showSubCommandHelp(args)
 	if len(args) == 0 {
-		if len(c.Args) != 0 || len(c.SubCommands) != 0 || c.parentCommand == nil {
+		if len(c.Args) != 0 || len(c.SubCommands) != 0 || c.ParentCommand == nil {
 			c.Usage()
 		}
-		if c.parentCommand != nil {
-			c.parentCommand.subcommand = c.Name
+		if c.ParentCommand != nil {
+			c.ParentCommand.subcommand = c.Name
 		}
 	}
 
+	vargs := args
+	for {
+		if len(vargs) == 0 {
+			break
+		}
+		var parsed bool
+		var err error
+		vargs, parsed, err = c.longOption(vargs)
+		if err != nil {
+			c.parseError(err.Error())
+		}
+		if parsed {
+			continue
+		}
+		vargs, parsed, err = c.shortOption(vargs)
+		if err != nil {
+			c.parseError(err.Error())
+		}
+		if parsed {
+			continue
+		}
+		if len(c.SubCommands) > 0 {
+			cmd := c.findSubcommand(args[0])
+			if cmd != nil {
+				c.subcommand = cmd.Name
+				vargs = vargs[1:]
+				vargs, err = cmd.Parse(vargs)
+				if err != nil {
+					c.parseError(err.Error())
+				}
+			} else {
+				c.parseError("Unknown subcommand " + args[0])
+			}
+		} else {
+			if c.ParentCommand != nil {
+				c.ParentCommand.remainArgs = append(c.ParentCommand.remainArgs, vargs[0])
+
+			} else {
+				c.remainArgs = append(c.remainArgs, vargs[0])
+			}
+			vargs = vargs[1:]
+
+		}
+	}
+	return vargs, nil
+}
+func (c *Command) findSubcommand(cmd string) *Command {
+	for _, subCmd := range c.SubCommands {
+		if subCmd.Name == cmd {
+			return subCmd
+		}
+	}
+	return nil
 }
 
 func (c *Command) longOption(args []string) ([]string, bool, error) {
@@ -98,8 +206,8 @@ func (c *Command) longOption(args []string) ([]string, bool, error) {
 			return args, false, err
 		}
 	}
-	if c.parentCommand != nil {
-		return c.parentCommand.longOption(args)
+	if c.ParentCommand != nil {
+		return c.ParentCommand.longOption(args)
 	}
 	return args, false, errors.New("Unknown option " + args[0])
 }
@@ -129,10 +237,10 @@ func (c *Command) shortOption(args []string) ([]string, bool, error) {
 			}
 
 		} else {
-			if c.parentCommand != nil {
-				opt = c.parentCommand.GetOption(string(s))
+			if c.ParentCommand != nil {
+				opt = c.ParentCommand.GetOption(string(s))
 				if opt != nil {
-					rargs, _, err := c.parentCommand.getOptValue(args[i:], opt, i != last)
+					rargs, _, err := c.ParentCommand.getOptValue(args[i:], opt, i != last)
 					if err == nil {
 						return rargs, true, nil
 					} else {
@@ -150,8 +258,8 @@ func (c *Command) shortOption(args []string) ([]string, bool, error) {
 func (c *Command) getOptValue(args []string, opt *Option, isFixBool bool) ([]string, interface{}, error) {
 
 	paramMap := c.globalOptions
-	if c.parentCommand != nil {
-		paramMap = c.parentCommand.subcommandOptions
+	if c.ParentCommand != nil {
+		paramMap = c.ParentCommand.subcommandOptions
 	}
 	if isFixBool {
 		if opt.OType != "bool" {
@@ -196,8 +304,18 @@ func (c *Command) getOptValue(args []string, opt *Option, isFixBool bool) ([]str
 				return args[2:], true, nil
 			}
 		case "default":
-			return args, nil, errors.New("Unsupported type")
+			return args, nil, errors.New("unsupported type")
 		}
 	}
-	return args, nil, errors.New("Unsupported type")
+	return args, nil, errors.New("unsupported type")
+}
+
+func NewCommand(name string, desc string) *Command {
+	return &Command{
+		Name:              name,
+		Description:       desc,
+		globalOptions:     map[string]interface{}{},
+		subcommandOptions: map[string]interface{}{},
+		remainArgs:        []string{},
+	}
 }
diff --git a/testcmd/main.go b/testcmd/main.go
new file mode 100644
index 0000000..6fc95da
--- /dev/null
+++ b/testcmd/main.go
@@ -0,0 +1,17 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"git.pyer.club/kingecg/command"
+)
+
+func main() {
+	var cmd = command.NewCommand("test", "test command")
+	cmd.AddArg("arg1", "a", "arg1 description", "default value")
+	cmd.AddArg("arg2", "b", "arg2 description", "default value")
+	cmd.AddSubCommand("sub1", "sub1 description")
+	cmd.Parse(os.Args[1:])
+	fmt.Println(cmd.GetGlobalOptions())
+}