@@ -11,6 +11,7 @@ import (

 	"fmt"

 	"io/ioutil"

 	"path/filepath"

+	"regexp"

 	"strings"

 	"github.com/docker/docker/nat"

@@ -129,7 +130,7 @@ func onbuild(b *Builder, args []string, attributes map[string]bool, original str

 		return fmt.Errorf("%s isn't allowed as an ONBUILD trigger", triggerInstruction)

 	}

-	original = strings.TrimSpace(strings.TrimLeft(original, "ONBUILD"))

+	original = regexp.MustCompile(`(?i)^\s*ONBUILD\s*`).ReplaceAllString(original, "")

 	b.Config.OnBuild = append(b.Config.OnBuild, original)

 	return b.commit("", b.Config.Cmd, fmt.Sprintf("ONBUILD %s", original))

@@ -15,6 +15,41 @@ import (

 	"github.com/docker/docker/pkg/archive"

 )

+func TestBuildOnBuildLowercase(t *testing.T) {

+	name := "testbuildonbuildlowercase"

+	name2 := "testbuildonbuildlowercase2"

+

+	defer deleteImages(name, name2)

+

+	_, err := buildImage(name,

+		`

+  FROM busybox

+  onbuild run echo quux

+  `, true)

+

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	_, out, err := buildImageWithOut(name2, fmt.Sprintf(`

+  FROM %s

+  `, name), true)

+

+	if err != nil {

+		t.Fatal(err)

+	}

+

+	if !strings.Contains(out, "quux") {

+		t.Fatalf("Did not receive the expected echo text, got %s", out)

+	}

+

+	if strings.Contains(out, "ONBUILD ONBUILD") {

+		t.Fatalf("Got an ONBUILD ONBUILD error with no error: got %s", out)

+	}

+

+	logDone("build - handle case-insensitive onbuild statement")

+}

+

 func TestBuildEnvEscapes(t *testing.T) {

 	name := "testbuildenvescapes"

 	defer deleteAllContainers()