func main() {
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	stdin, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	flag.Merge(flag.CommandLine, clientFlags.FlagSet, commonFlags.FlagSet)

	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: docker [OPTIONS] COMMAND [arg...]\n"+daemonUsage+"       docker [ -h | --help | -v | --version ]\n\n")
		fmt.Fprint(os.Stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		for _, cmd := range dockerCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.name, cmd.description)
		}

		help += "\nRun 'docker COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stdout, "%s\n", help)
	}

	flag.Parse()

	if *flVersion {
		showVersion()
		return
	}

	clientCli := client.NewDockerCli(stdin, stdout, stderr, clientFlags)
	// TODO: remove once `-d` is retired
	handleGlobalDaemonFlag()

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	c := cli.New(clientCli, daemonCli)
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(os.Stderr, sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

func main() {
	if help {
		flag.PrintDefaults()
	} else {
		target := flag.Arg(0)

		if keys.Len() == 0 {
			fmt.Fprintln(os.Stderr, "WARNING: No signing keys specified, upload *DISABLED*")
		}

		if target != "" {
			strkeys := keys.GetAll()
			digest, manifest, err := processTarget(target, strkeys)
			if err != nil {
				fmt.Printf("Error processing target: %s\n", err)
				os.Exit(1)
			}

			if verbose {
				fmt.Println(manifest)
			}
			fmt.Printf("Done! Referencing digest: %s\n", digest)
		}
	}

	os.Exit(0)
}

func main() {
	switch {
	case h:
		flag.PrintDefaults()
	case server:
		// TODO: Better way to copy these arguments to sshd?
		sshcamArgs := []string{
			"--device=" + device,
			"--size=" + sizeFlag,
			"--color-algorithm=" + distanceAlgorithm,
			"--max-fps=" + strconv.Itoa(maxFPS)}
		if colorful {
			sshcamArgs = append(sshcamArgs, "--color")
		}
		if asciiOnly {
			sshcamArgs = append(sshcamArgs, "--ascii-only")
		}
		sshd.Run(user, pass, listen, strconv.Itoa(port), sshcamArgs)
	default:
		var wg sync.WaitGroup

		// Initialize the webcam device
		webcam.OpenWebcam(device, size.Width, size.Height)
		defer webcam.CloseWebcam()

		// Start the TTY size updater goroutine
		ttyStatus := updateTTYSize()

		// Fire the drawing goroutine
		wg.Add(1)
		go streaming(ttyStatus, &wg)
		wg.Wait()
	}
}

func init() {
	var placeholderTrustKey string
	// TODO use flag flag.String([]string{"i", "-identity"}, "", "Path to libtrust key file")
	flTrustKey = &placeholderTrustKey

	flag.StringVar(&tlsOptions.CAFile, []string{"-tlscacert"}, filepath.Join(dockerCertPath, defaultCaFile), "Trust certs signed only by this CA")
	flag.StringVar(&tlsOptions.CertFile, []string{"-tlscert"}, filepath.Join(dockerCertPath, defaultCertFile), "Path to TLS certificate file")
	flag.StringVar(&tlsOptions.KeyFile, []string{"-tlskey"}, filepath.Join(dockerCertPath, defaultKeyFile), "Path to TLS key file")
	opts.HostListVar(&flHosts, []string{"H", "-host"}, "Daemon socket(s) to connect to")

	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: docker [OPTIONS] COMMAND [arg...]\n\nA self-sufficient runtime for linux containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		sort.Sort(byName(dockerCommands))

		for _, cmd := range dockerCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.name, cmd.description)
		}

		help += "\nRun 'docker COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stdout, "%s\n", help)
	}
}

func init() {
	flCa = flag.String([]string{"-tlscacert"}, filepath.Join(dockerCertPath, defaultCaFile), "Trust only remotes providing a certificate signed by the CA given here")
	flCert = flag.String([]string{"-tlscert"}, filepath.Join(dockerCertPath, defaultCertFile), "Path to TLS certificate file")
	flKey = flag.String([]string{"-tlskey"}, filepath.Join(dockerCertPath, defaultKeyFile), "Path to TLS key file")
	opts.HostListVar(&flHosts, []string{"H", "-host"}, "The socket(s) to bind to in daemon mode or connect to in client mode, specified using one or more tcp://host:port, unix:///path/to/socket, fd://* or fd://socketfd.")

	flag.Usage = func() {
		fmt.Fprint(os.Stderr, "Usage: docker [OPTIONS] COMMAND [arg...]\n\nA self-sufficient runtime for linux containers.\n\nOptions:\n")

		flag.PrintDefaults()

		help := "\nCommands:\n"

		for _, command := range [][]string{
			{"attach", "Attach to a running container"},
			{"build", "Build an image from a Dockerfile"},
			{"commit", "Create a new image from a container's changes"},
			{"cp", "Copy files/folders from a container's filesystem to the host path"},
			{"create", "Create a new container"},
			{"diff", "Inspect changes on a container's filesystem"},
			{"events", "Get real time events from the server"},
			{"exec", "Run a command in an existing container"},
			{"export", "Stream the contents of a container as a tar archive"},
			{"history", "Show the history of an image"},
			{"images", "List images"},
			{"import", "Create a new filesystem image from the contents of a tarball"},
			{"info", "Display system-wide information"},
			{"inspect", "Return low-level information on a container"},
			{"kill", "Kill a running container"},
			{"load", "Load an image from a tar archive"},
			{"login", "Register or log in to a Docker registry server"},
			{"logout", "Log out from a Docker registry server"},
			{"logs", "Fetch the logs of a container"},
			{"port", "Lookup the public-facing port that is NAT-ed to PRIVATE_PORT"},
			{"pause", "Pause all processes within a container"},
			{"ps", "List containers"},
			{"pull", "Pull an image or a repository from a Docker registry server"},
			{"push", "Push an image or a repository to a Docker registry server"},
			{"restart", "Restart a running container"},
			{"rm", "Remove one or more containers"},
			{"rmi", "Remove one or more images"},
			{"run", "Run a command in a new container"},
			{"save", "Save an image to a tar archive"},
			{"search", "Search for an image on the Docker Hub"},
			{"start", "Start a stopped container"},
			{"stop", "Stop a running container"},
			{"tag", "Tag an image into a repository"},
			{"top", "Lookup the running processes of a container"},
			{"unpause", "Unpause a paused container"},
			{"version", "Show the Docker version information"},
			{"wait", "Block until a container stops, then print its exit code"},
		} {
			help += fmt.Sprintf("    %-10.10s%s\n", command[0], command[1])
		}
		help += "\nRun 'docker COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stderr, "%s\n", help)
	}
}

func main() {
	if help {
		flag.PrintDefaults()
	} else {
		target := flag.Arg(0)
		if target != "" {
			//fmt.Printf("outputting manifest for: %q with key: %q\n", target, key)
			outputManifestFor(target)
		}
	}
}

func main() {
	if h {
		flag.PrintDefaults()
	} else {
		fmt.Printf("s/#hidden/-string: %s\n", str)
		fmt.Printf("b: %t\n", b)
		fmt.Printf("-bool: %t\n", b2)
		fmt.Printf("s/#hidden/-string(via lookup): %s\n", flag.Lookup("s").Value.String())
		fmt.Printf("ARGS: %v\n", flag.Args())
	}
}

func main() {
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	_, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	flag.Merge(flag.CommandLine, daemonCli.commonFlags.FlagSet)

	flag.Usage = func() {
		fmt.Fprint(stdout, "Usage: dockerd [ --help | -v | --version ]\n\n")
		fmt.Fprint(stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(stdout)
		flag.PrintDefaults()
	}
	flag.CommandLine.ShortUsage = func() {
		fmt.Fprint(stderr, "\nUsage:\tdockerd [OPTIONS]\n")
	}

	if err := flag.CommandLine.ParseFlags(os.Args[1:], false); err != nil {
		os.Exit(1)
	}

	if *flVersion {
		showVersion()
		return
	}

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	// On Windows, this may be launching as a service or with an option to
	// register the service.
	stop, err := initService()
	if err != nil {
		logrus.Fatal(err)
	}

	if !stop {
		err = daemonCli.start()
		notifyShutdown(err)
		if err != nil {
			logrus.Fatal(err)
		}
	}
}

func main() {
	fmt.Print("Hello, world\n")

	// Define global flag here

	// end global flag definition

	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: docking [OPTIONS] COMMAND [arg...]\n       docking [ --help | -v | --version ]\n\n")
		fmt.Fprint(os.Stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		for _, cmd := range dockingCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.Name, cmd.Description)
		}

		help += "\nRun 'docking COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stdout, "%s\n", help)
	}
	flag.Parse()

	if *flVersion {
		showVersion()
		return
	}

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	clientCli := client.NewDockingCli(os.Stdin, os.Stdout, os.Stderr, clientFlags)

	c := cli.New(clientCli)
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(os.Stderr, sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}

}

func init() {
	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: dnet [OPTIONS] COMMAND [arg...]\n\nA self-sufficient runtime for container networking.\n\nOptions:\n")

		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		for _, cmd := range dnetCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.name, cmd.description)
		}

		help += "\nRun 'dnet COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stdout, "%s\n", help)
	}
}

// doFlags defines the cmdline Usage string and parses flag options.
func doFlags() {
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "  Usage: %s [OPTIONS] REGISTRY REPO [REPO...]\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "\n  REGISTRY:\n")
		fmt.Fprintf(os.Stderr, "\tURL of your Docker registry; use index.docker.io for Docker Hub, use local.host to collect images from local Docker host\n")
		fmt.Fprintf(os.Stderr, "\n  REPO:\n")
		fmt.Fprintf(os.Stderr, "\tOne or more repos to gather info about; if no repo is specified Collector will gather info on *all* repos in the Registry\n")
		fmt.Fprintf(os.Stderr, "\n  Environment variables:\n")
		fmt.Fprintf(os.Stderr, "\tCOLLECTOR_DIR:   (Required) Directory that contains the \"data\" folder with Collector default scripts, e.g., $GOPATH/src/github.com/banyanops/collector\n")
		fmt.Fprintf(os.Stderr, "\tCOLLECTOR_ID:    ID provided by Banyan web interface to register Collector with the Banyan service\n")
		fmt.Fprintf(os.Stderr, "\tBANYAN_HOST_DIR: Host directory mounted into Collector/Target containers where results are stored (default: $HOME/.banyan)\n")
		fmt.Fprintf(os.Stderr, "\tBANYAN_DIR:      (Specify only in Dockerfile) Directory in the Collector container where host directory BANYAN_HOST_DIR is mounted\n")
		fmt.Fprintf(os.Stderr, "\tDOCKER_{HOST,CERT_PATH,TLS_VERIFY}: If set, e.g., by docker-machine, then they take precedence over --dockerProto and --dockerAddr\n")
		printExampleUsage()
		fmt.Fprintf(os.Stderr, "  Options:\n")
		flag.PrintDefaults()
	}
	flag.Parse()
	if config.COLLECTORDIR() == "" {
		flag.Usage()
		os.Exit(except.ErrorExitStatus)
	}
	if len(flag.Args()) < 1 {
		flag.Usage()
		os.Exit(except.ErrorExitStatus)
	}
	if *dockerProto != "unix" && *dockerProto != "tcp" {
		flag.Usage()
		os.Exit(except.ErrorExitStatus)
	}
	requiredDirs := []string{config.BANYANDIR(), filepath.Dir(*imageList), filepath.Dir(*repoList), *config.BanyanOutDir, collector.DefaultScriptsDir, collector.UserScriptsDir, collector.BinDir}
	for _, dir := range requiredDirs {
		blog.Debug("Creating directory: " + dir)
		err := fsutil.CreateDirIfNotExist(dir)
		if err != nil {
			except.Fail(err, ": Error in creating a required directory: ", dir)
		}
	}
	collector.RegistrySpec = flag.Arg(0)
	// EqualFold: case insensitive comparison
	if strings.EqualFold(flag.Arg(0), "local.host") {
		collector.LocalHost = true
	}
	//nextMaxImages = *maxImages
}

func main() {
	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: gofind [OPTIONS] COMMAND [arg...]\ngofind [ --help | -v | --version ]\n")
		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()
	}
	if h {
		flag.Usage()
	} else {
		fmt.Printf("Path: %s\n", path)
		fmt.Printf("Name: %s\n", name)
		fmt.Printf("ARGS: %v\n", flag.Args())
		err := finder(path, name)
		if err != nil {
			fmt.Println(err)
			return
		}

	}
}

func main() {
	switch {
	case h:
		flag.PrintDefaults()
	default:
		m := martini.Classic()

		m.Use(render.Renderer())

		m.Use(cors.Allow(&cors.Options{
			AllowOrigins: []string{"*"},
			AllowHeaders: []string{"Origin"},
		}))

		m.Get("/user/:id", GetUserLogs)
		m.Get("/repo/:name", GetRepoLogs)

		m.Run()
	}
}

func main() {
	if help {
		mflag.PrintDefaults()
		return
	}

	config, err := config.ReadConfig(conffile, env)
	if err != nil {
		logrus.Errorln("main", err)
		return
	}
	var distribute distributed.Distributed
	if master {
		distribute = &distributed.Master{}
	} else {
		distribute = &distributed.Slave{}
	}
	distribute.Init(config)
	distribute.Done("str")
}

func Usage() {
	fmt.Printf("Usage: %s [options]\n\n%s", os.Args[0], "Options:")
	flag.PrintDefaults()
	os.Exit(retOk)
}

func main() {
	//启动前检查，防止出现已经启动的情况
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	stdin, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	//合并参数类型，所有的参数类型都是FlagSet类，该类定义如下：
	//type FlagSet struct {
	// Usage is the function called when an error occurs while parsing flags.
	// The field is a function (not a method) that may be changed to point to
	// a custom error handler.
	/*Usage      func()
		ShortUsage func()

		name             string
		parsed           bool
		actual           map[string]*Flag
		formal           map[string]*Flag
		args             []string // arguments after flags
		errorHandling    ErrorHandling
		output           io.Writer // nil means stderr; use Out() accessor
		nArgRequirements []nArgRequirement
	}*/
	//合并参数到flag.CommandLine中。CommandLine中对应的是Options。
	flag.Merge(flag.CommandLine, clientFlags.FlagSet, commonFlags.FlagSet)

	//打印docker的使用方式。这里其实只是设置Usage这个函数的实现，以便需要打印的时候打印。
	flag.Usage = func() {
		//第一行是正常的使用方式；第二行是daemon的使用方式；第三行固定输出
		fmt.Fprint(stdout, "Usage: docker [OPTIONS] COMMAND [arg...]\n"+daemonUsage+"       docker [ --help | -v | --version ]\n\n")
		fmt.Fprint(stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		//输出Options的内容，打印CommandLine中的内容。这一行设置输出到标准输出。
		flag.CommandLine.SetOutput(stdout)
		//真实的打印内容
		flag.PrintDefaults()

		//开始打印可选择的命令Commands。
		help := "\nCommands:\n"

		//循环输出dockerCommands命令中的可选择命令，分别打印他们的名字和描述信息。
		//dockerCommands最终由cli.DockerCommands中提供。
		for _, cmd := range dockerCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.Name, cmd.Description)
		}

		help += "\nRun 'docker COMMAND --help' for more information on a command."
		//真实的打印
		fmt.Fprintf(stdout, "%s\n", help)
	}

	//解析参数
	flag.Parse()

	//version单独处理，这里通过判断flVersion的返回结果是否为真进行处理。
	if *flVersion {
		showVersion()
		return
	}
	//help信息单独处理
	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	//创建client模式的docker，详细分析请见api/client/cli.go包中的NewDockerCli函数。
	clientCli := client.NewDockerCli(stdin, stdout, stderr, clientFlags)

	//合并client模式的docker和daemonCli模式的docker，实际中只会有一个在工作。
	//daemonCli对象的创建请见docker/daemon.go中的daemonCli cli.Handler = NewDaemonCli()
	//cli.New接受两个参数，分别是dockercli对象和daemoncli对象，两个对象结构不同。
	//但是返回的是一个cli对象:
	/*
			type Cli struct {
			    Stderr   io.Writer
			    handlers []Handler
			    Usage    func()
		            }
	*/
	//clientClie和daemoncli就放在句柄handlers数组中。
	c := cli.New(clientCli, daemonCli)
	//c.Run函数见cli中的cli.go的func (cli *Cli) Run(args ...string) error
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(stderr, sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(stderr, err)
		os.Exit(1)
	}
//.........这里部分代码省略.........

// TODO rewrite this whole PoC
func main() {
	flag.Usage = func() {
		flag.PrintDefaults()
	}
	flag.Parse()
	if debug {
		os.Setenv("DEBUG", "1")
		log.SetLevel(log.DebugLevel)
	}
	if flag.NArg() == 0 {
		fmt.Println("ERROR: no image names provided")
		flag.Usage()
		os.Exit(1)
	}

	// make tempDir
	tempDir, err := ioutil.TempDir("", "docker-fetch-")
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	defer os.RemoveAll(tempDir)

	fetcher := NewFetcher(tempDir)
	sc := registry.NewServiceConfig(rOptions)

	for _, arg := range flag.Args() {
		remote, tagName := parsers.ParseRepositoryTag(arg)
		if tagName == "" {
			tagName = "latest"
		}

		repInfo, err := sc.NewRepositoryInfo(remote)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		log.Debugf("%#v %q\n", repInfo, tagName)

		idx, err := repInfo.GetEndpoint()
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		fmt.Fprintf(os.Stderr, "Pulling %s:%s from %s\n", repInfo.RemoteName, tagName, idx)

		var session *registry.Session
		if s, ok := fetcher.sessions[idx.String()]; ok {
			session = s
		} else {
			// TODO(vbatts) obviously the auth and http factory shouldn't be nil here
			session, err = registry.NewSession(nil, nil, idx, timeout)
			if err != nil {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}
		}

		rd, err := session.GetRepositoryData(repInfo.RemoteName)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		log.Debugf("rd: %#v", rd)

		// produce the "repositories" file for the archive
		if _, ok := fetcher.repositories[repInfo.RemoteName]; !ok {
			fetcher.repositories[repInfo.RemoteName] = graph.Repository{}
		}
		log.Debugf("repositories: %#v", fetcher.repositories)

		if len(rd.Endpoints) == 0 {
			log.Fatalf("expected registry endpoints, but received none from the index")
		}

		tags, err := session.GetRemoteTags(rd.Endpoints, repInfo.RemoteName, rd.Tokens)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		if hash, ok := tags[tagName]; ok {
			fetcher.repositories[repInfo.RemoteName][tagName] = hash
		}
		log.Debugf("repositories: %#v", fetcher.repositories)

		imgList, err := session.GetRemoteHistory(fetcher.repositories[repInfo.RemoteName][tagName], rd.Endpoints[0], rd.Tokens)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		log.Debugf("imgList: %#v", imgList)

		for _, imgID := range imgList {
			// pull layers and jsons
			buf, _, err := session.GetRemoteImageJSON(imgID, rd.Endpoints[0], rd.Tokens)
			if err != nil {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}
//.........这里部分代码省略.........

func main() {
	// Set terminal emulation based on platform as required.
	stdin, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	flag.Merge(flag.CommandLine, clientFlags.FlagSet, commonFlags.FlagSet)

	cobraAdaptor := cobraadaptor.NewCobraAdaptor(clientFlags)

	flag.Usage = func() {
		fmt.Fprint(stdout, "Usage: docker [OPTIONS] COMMAND [arg...]\n       docker [ --help | -v | --version ]\n\n")
		fmt.Fprint(stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		dockerCommands := append(cli.DockerCommandUsage, cobraAdaptor.Usage()...)
		for _, cmd := range sortCommands(dockerCommands) {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.Name, cmd.Description)
		}

		help += "\nRun 'docker COMMAND --help' for more information on a command."
		fmt.Fprintf(stdout, "%s\n", help)
	}

	flag.Parse()

	if *flVersion {
		showVersion()
		return
	}

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	clientCli := client.NewDockerCli(stdin, stdout, stderr, clientFlags)

	c := cli.New(clientCli, NewDaemonProxy(), cobraAdaptor)
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(stderr, sterr.Status)
			}
			// StatusError should only be used for errors, and all errors should
			// have a non-zero exit status, so never exit with 0
			if sterr.StatusCode == 0 {
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(stderr, err)
		os.Exit(1)
	}
}

func main() {
	flag.Usage = func() {
		flag.PrintDefaults()
	}
	flag.Parse()
	if debug {
		os.Setenv("DEBUG", "1")
		logrus.SetLevel(logrus.DebugLevel)
	}
	if flag.NArg() == 0 {
		flag.Usage()
		logrus.Fatal("no image names provided")
	}

	// make temporary working directory
	tempFetchRoot, err := ioutil.TempDir("", "docker-fetch-")
	if err != nil {
		logrus.Fatal(err)
	}

	refs := []*fetch.ImageRef{}
	for _, arg := range flag.Args() {
		ref := fetch.NewImageRef(arg)
		fmt.Fprintf(os.Stderr, "Pulling %s\n", ref)
		r := fetch.NewRegistry(ref.Host())

		layersFetched, err := r.FetchLayers(ref, tempFetchRoot)
		if err != nil {
			logrus.Errorf("failed pulling %s, skipping: %s", ref, err)
			continue
		}
		logrus.Debugf("fetched %d layers for %s", len(layersFetched), ref)
		refs = append(refs, ref)
	}

	// marshal the "repositories" file for writing out
	buf, err := fetch.FormatRepositories(refs...)
	if err != nil {
		logrus.Fatal(err)
	}
	fh, err := os.Create(filepath.Join(tempFetchRoot, "repositories"))
	if err != nil {
		logrus.Fatal(err)
	}
	if _, err = fh.Write(buf); err != nil {
		logrus.Fatal(err)
	}
	fh.Close()
	logrus.Debugf("%s", fh.Name())

	var output io.WriteCloser
	if outputStream == "-" {
		output = os.Stdout
	} else {
		output, err = os.Create(outputStream)
		if err != nil {
			logrus.Fatal(err)
		}
	}
	defer output.Close()

	if err = os.Chdir(tempFetchRoot); err != nil {
		logrus.Fatal(err)
	}
	tarStream, err := archive.Tar(".", archive.Uncompressed)
	if err != nil {
		logrus.Fatal(err)
	}
	if _, err = io.Copy(output, tarStream); err != nil {
		logrus.Fatal(err)
	}
}