@@ -25,14 +25,14 @@ func (cli *DockerCli) dial() (net.Conn, error) {

 	return net.Dial(cli.proto, cli.addr)

 }

-func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.ReadCloser, stdout, stderr io.Writer, started chan io.Closer, body interface{}) error {

+func (cli *DockerCli) hijack(method, path string, setRawTerminal bool, in io.ReadCloser, stdout, stderr io.Writer, started chan io.Closer, data interface{}) error {

 	defer func() {

 		if started != nil {

 			close(started)

 		}

 	}()

-	params, err := cli.getUrlBody(body)

+	params, err := cli.encodeData(data)

 	if err != nil {

 		return err

 	}

@@ -40,7 +40,7 @@ func (cli *DockerCli) HTTPClient() *http.Client {

 	return &http.Client{Transport: tr}

 }

-func (cli *DockerCli) getUrlBody(data interface{}) (*bytes.Buffer, error) {

+func (cli *DockerCli) encodeData(data interface{}) (*bytes.Buffer, error) {

 	params := bytes.NewBuffer(nil)

 	if data != nil {

 		if env, ok := data.(engine.Env); ok {

@@ -61,7 +61,7 @@ func (cli *DockerCli) getUrlBody(data interface{}) (*bytes.Buffer, error) {

 }

 func (cli *DockerCli) call(method, path string, data interface{}, passAuthInfo bool) (io.ReadCloser, int, error) {

-	params, err := cli.getUrlBody(data)

+	params, err := cli.encodeData(data)

 	if err != nil {

 		return nil, -1, err

 	}

@@ -128,7 +128,7 @@ func (daemon *Daemon) Attach(streamConfig *StreamConfig, openStdin, stdinOnce, t

 	// Connect stdin of container to the http conn.

 	if stdin != nil && openStdin {

-		nJobs += 1

+		nJobs++

 		// Get the stdin pipe.

 		if cStdin, err := streamConfig.StdinPipe(); err != nil {

 			errors <- err

@@ -166,7 +166,7 @@ func (daemon *Daemon) Attach(streamConfig *StreamConfig, openStdin, stdinOnce, t

 		}

 	}

 	if stdout != nil {

-		nJobs += 1

+		nJobs++

 		// Get a reader end of a pipe that is attached as stdout to the container.

 		if p, err := streamConfig.StdoutPipe(); err != nil {

 			errors <- err

@@ -260,7 +260,7 @@ func (daemon *Daemon) Attach(streamConfig *StreamConfig, openStdin, stdinOnce, t

 		// FIXME: how to clean up the stdin goroutine without the unwanted side effect

 		// of closing the passed stdin? Add an intermediary io.Pipe?

-		for i := 0; i < nJobs; i += 1 {

+		for i := 0; i < nJobs; i++ {

 			log.Debugf("attach: waiting for job %d/%d", i+1, nJobs)

 			if err := <-errors; err != nil {

 				log.Errorf("attach: job %d returned error %s, aborting all jobs", i+1, err)

@@ -24,7 +24,7 @@ type ExecConfig struct {

 func (d *Daemon) ContainerExec(job *engine.Job) engine.Status {

 	if len(job.Args) != 1 {

-		return job.Errorf("Usage: %s container_id command", job.Name)

+		return job.Errorf("Usage: %s [options] container command [args]", job.Name)

 	}

 	var (

@@ -40,7 +40,7 @@ func (d *Daemon) ContainerExec(job *engine.Job) engine.Status {

 		return job.Errorf("No such container: %s", name)

 	}

-	if !container.State.IsRunning() {

+	if !container.IsRunning() {

 		return job.Errorf("Container %s is not not running", name)

 	}

@@ -16,15 +16,16 @@ import (

 	"github.com/docker/libcontainer/namespaces"

 )

-const commandName = "nsenter-exec"

+const execCommandName = "nsenter-exec"

 func init() {

-	reexec.Register(commandName, nsenterExec)

+	reexec.Register(execCommandName, nsenterExec)

 }

 func nsenterExec() {

 	runtime.LockOSThread()

+	// User args are passed after '--' in the command line.

 	userArgs := findUserArgs()

 	config, err := loadConfigFromFd()

@@ -10,16 +10,12 @@ import (

 )

 func findUserArgs() []string {

-	i := 0

-	for _, a := range os.Args {

-		i++

-

+	for i, a := range os.Args {

 		if a == "--" {

-			break

+			return os.Args[i+1:]

 		}

 	}

-

-	return os.Args[i:]

+	return []string{}

 }

 // loadConfigFromFd loads a container's config from the sync pipe that is provided by

@@ -1297,7 +1297,7 @@ It is even useful to cherry-pick particular tags of an image repository

 ## exec

-    Usage: docker exec CONTAINER COMMAND [ARG...]

+    Usage: docker exec [OPTIONS] CONTAINER COMMAND [ARG...]

     Run a command in an existing container

@@ -27,8 +27,8 @@ func ExecConfigFromJob(job *engine.Job) *ExecConfig {

 		AttachStderr: job.GetenvBool("AttachStderr"),

 		AttachStdout: job.GetenvBool("AttachStdout"),

 	}

-	if Cmd := job.GetenvList("Cmd"); Cmd != nil {

-		execConfig.Cmd = Cmd

+	if cmd := job.GetenvList("Cmd"); cmd != nil {

+		execConfig.Cmd = cmd

 	}

 	return execConfig