@@ -619,7 +619,7 @@ func (b *Builder) run(c *daemon.Container) error {

 	// Wait for it to finish

 	if ret, _ := c.WaitStop(-1 * time.Second); ret != 0 {

 		return &jsonmessage.JSONError{

-			Message: fmt.Sprintf("The command %v returned a non-zero code: %d", b.Config.Cmd, ret),

+			Message: fmt.Sprintf("The command %q returned a non-zero code: %d", b.Config.Cmd.ToString(), ret),

 			Code:    ret,

 		}

 	}

@@ -5384,3 +5384,20 @@ func (s *DockerSuite) TestBuildBadCmdFlag(c *check.C) {

 		c.Fatalf("Bad output\nGot:%s\n\nExpected to contain:%s\n", out, exp)

 	}

 }

+

+func (s *DockerSuite) TestBuildRUNErrMsg(c *check.C) {

+	// Test to make sure the bad command is quoted with just "s and

+	// not as a Go []string

+	name := "testbuildbadrunerrmsg"

+	_, out, err := buildImageWithOut(name, `

+  FROM busybox

+  RUN badEXE a1 a2`, false)

+	if err == nil {

+		c.Fatal("Should have failed to build")

+	}

+

+	exp := `The command \"/bin/sh -c badEXE a1 a2\" returned a non-zero code: 127"`

+	if !strings.Contains(out, exp) {

+		c.Fatalf("RUN doesn't have the correct output:\nGot:%s\nExpected:%s", out, exp)

+	}

+}

@@ -3,6 +3,7 @@ package runconfig

 import (

 	"encoding/json"

 	"io"

+	"strings"

 	"github.com/docker/docker/nat"

 )

@@ -59,6 +60,10 @@ type Command struct {

 	parts []string

 }

+func (e *Command) ToString() string {

+	return strings.Join(e.parts, " ")

+}

+

 func (e *Command) MarshalJSON() ([]byte, error) {

 	if e == nil {

 		return []byte{}, nil