@@ -112,9 +112,8 @@ func (cli *DockerCli) CmdInsert(args ...string) error {

 }

 func (cli *DockerCli) CmdBuild(args ...string) error {

-	cmd := Subcmd("build", "[OPTIONS]", "Build an image from a Dockerfile")

-	fileName := cmd.String("f", "Dockerfile", "Use file as Dockerfile. Can be '-' for stdin")

-	contextPath := cmd.String("c", "", "Use the specified directory as context for the build")

+	cmd := Subcmd("build", "[OPTIONS] [CONTEXT]", "Build an image from a Dockerfile")

+	fileName := cmd.String("f", "Dockerfile", "Use `file` as Dockerfile. Can be '-' for stdin")

 	if err := cmd.Parse(args); err != nil {

 		return nil

 	}

@@ -146,14 +145,16 @@ func (cli *DockerCli) CmdBuild(args ...string) error {

 	}

 	multipartBody = io.MultiReader(multipartBody, file)

+	compression := Bzip2

+

 	// Create a FormFile multipart for the context if needed

-	if *contextPath != "" {

+	if cmd.Arg(0) != "" {

 		// FIXME: Use NewTempArchive in order to have the size and avoid too much memory usage?

-		context, err := Tar(*contextPath, Bzip2)

+		context, err := Tar(cmd.Arg(0), compression)

 		if err != nil {

 			return err

 		}

-		if _, err := w.CreateFormFile("Context", *contextPath+".tar.bz2"); err != nil {

+		if _, err := w.CreateFormFile("Context", cmd.Arg(0)+"."+compression.Extension()); err != nil {

 			return err

 		}

 		multipartBody = io.MultiReader(multipartBody, utils.ProgressReader(ioutil.NopCloser(context), -1, os.Stdout, "Uploading Context %v/%v (%v)"))

@@ -165,6 +166,9 @@ func (cli *DockerCli) CmdBuild(args ...string) error {

 		return err

 	}

 	req.Header.Set("Content-Type", w.FormDataContentType())

+	if cmd.Arg(0) != "" {

+		req.Header.Set("X-Docker-Context-Compression", compression.Flag())

+	}

 	resp, err := http.DefaultClient.Do(req)

 	if err != nil {