diff --git a/command/build_test.go b/command/build_test.go
new file mode 100644
index 000000000..73837e1a2
--- /dev/null
+++ b/command/build_test.go
@@ -0,0 +1,132 @@
+package command
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/mitchellh/packer/builder/file"
+	"github.com/mitchellh/packer/packer"
+)
+
+func TestBuildOnlyFileCommaFlags(t *testing.T) {
+	c := &BuildCommand{
+		Meta: testMetaFile(t),
+	}
+
+	args := []string{
+		"-only=chocolate,vanilla",
+		filepath.Join(testFixture("build-only"), "template.json"),
+	}
+
+	defer cleanup()
+
+	if code := c.Run(args); code != 0 {
+		fatalCommand(t, c.Meta)
+	}
+
+	if !fileExists("chocolate.txt") {
+		t.Error("Expected to find chocolate.txt")
+	}
+	if !fileExists("vanilla.txt") {
+		t.Error("Expected to find vanilla.txt")
+	}
+	if fileExists("cherry.txt") {
+		t.Error("Expected NOT to find cherry.txt")
+	}
+}
+
+func TestBuildOnlyFileMultipleFlags(t *testing.T) {
+	c := &BuildCommand{
+		Meta: testMetaFile(t),
+	}
+
+	args := []string{
+		"-only=chocolate",
+		"-only=cherry",
+		filepath.Join(testFixture("build-only"), "template.json"),
+	}
+
+	defer cleanup()
+
+	if code := c.Run(args); code != 0 {
+		fatalCommand(t, c.Meta)
+	}
+
+	if !fileExists("chocolate.txt") {
+		t.Error("Expected to find chocolate.txt")
+	}
+	if fileExists("vanilla.txt") {
+		t.Error("Expected NOT to find vanilla.txt")
+	}
+	if !fileExists("cherry.txt") {
+		t.Error("Expected to find cherry.txt")
+	}
+}
+
+func TestBuildExceptFileCommaFlags(t *testing.T) {
+	c := &BuildCommand{
+		Meta: testMetaFile(t),
+	}
+
+	args := []string{
+		"-except=chocolate",
+		filepath.Join(testFixture("build-only"), "template.json"),
+	}
+
+	defer cleanup()
+
+	if code := c.Run(args); code != 0 {
+		fatalCommand(t, c.Meta)
+	}
+
+	if fileExists("chocolate.txt") {
+		t.Error("Expected NOT to find chocolate.txt")
+	}
+	if !fileExists("vanilla.txt") {
+		t.Error("Expected to find vanilla.txt")
+	}
+	if !fileExists("cherry.txt") {
+		t.Error("Expected to find cherry.txt")
+	}
+}
+
+// fileExists returns true if the filename is found
+func fileExists(filename string) bool {
+	if _, err := os.Stat(filename); err == nil {
+		return true
+	}
+	return false
+}
+
+// testCoreConfigBuilder creates a packer CoreConfig that has a file builder
+// available. This allows us to test a builder that writes files to disk.
+func testCoreConfigBuilder(t *testing.T) *packer.CoreConfig {
+	components := packer.ComponentFinder{
+		Builder: func(n string) (packer.Builder, error) {
+			return &file.Builder{}, nil
+		},
+	}
+	return &packer.CoreConfig{
+		Components: components,
+	}
+}
+
+// testMetaFile creates a Meta object that includes a file builder
+func testMetaFile(t *testing.T) Meta {
+	var out, err bytes.Buffer
+	return Meta{
+		CoreConfig: testCoreConfigBuilder(t),
+		Ui: &packer.BasicUi{
+			Writer:      &out,
+			ErrorWriter: &err,
+		},
+	}
+}
+
+func cleanup() {
+	os.RemoveAll("chocolate.txt")
+	os.RemoveAll("vanilla.txt")
+	os.RemoveAll("cherry.txt")
+}
diff --git a/command/test-fixtures/build-only/template.json b/command/test-fixtures/build-only/template.json
new file mode 100644
index 000000000..ee89d635e
--- /dev/null
+++ b/command/test-fixtures/build-only/template.json
@@ -0,0 +1,22 @@
+{
+    "builders": [
+        {
+            "name":"chocolate",
+            "type":"file",
+            "content":"chocolate",
+            "target":"chocolate.txt"
+        },
+        {
+            "name":"vanilla",
+            "type":"file",
+            "content":"vanilla",
+            "target":"vanilla.txt"
+        },
+        {
+            "name":"cherry",
+            "type":"file",
+            "content":"cherry",
+            "target":"cherry.txt"
+        }
+    ]
+}
diff --git a/helper/flag-slice/flag.go b/helper/flag-slice/flag.go
index da75149dc..587b674fa 100644
--- a/helper/flag-slice/flag.go
+++ b/helper/flag-slice/flag.go
@@ -11,6 +11,6 @@ func (s *StringFlag) String() string {
 }
 
 func (s *StringFlag) Set(value string) error {
-	*s = append(*s, value)
+	*s = append(*s, strings.Split(value, ",")...)
 	return nil
 }
diff --git a/helper/flag-slice/flag_test.go b/helper/flag-slice/flag_test.go
index f72e1d960..61d8682b2 100644
--- a/helper/flag-slice/flag_test.go
+++ b/helper/flag-slice/flag_test.go
@@ -14,6 +14,8 @@ func TestStringFlag_implements(t *testing.T) {
 	}
 }
 
+// TestStringFlagSet tests for setting the same flag more than once on the CLI
+// like: blah -flag foo -flag bar
 func TestStringFlagSet(t *testing.T) {
 	sv := new(StringFlag)
 	err := sv.Set("foo")
@@ -31,3 +33,18 @@ func TestStringFlagSet(t *testing.T) {
 		t.Fatalf("Bad: %#v", sv)
 	}
 }
+
+// TestMultiStringFlag tests for setting the same flag using a comma-separated
+// list of items like: blah -flag=foo,bar
+func TestMultiStringFlag(t *testing.T) {
+	sv := new(StringFlag)
+	err := sv.Set("chocolate,vanilla")
+	if err != nil {
+		t.Fatalf("err :%s", err)
+	}
+
+	expected := []string{"chocolate", "vanilla"}
+	if !reflect.DeepEqual([]string(*sv), expected) {
+		t.Fatalf("Expected: %#v, found: %#v", expected, sv)
+	}
+}