diff --git a/cmd/helm/init.go b/cmd/helm/init.go
index c7bfba482..2a2a3c331 100644
--- a/cmd/helm/init.go
+++ b/cmd/helm/init.go
@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"strings"
 
 	"github.com/spf13/cobra"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -123,7 +122,7 @@ func newInitCmd(out io.Writer) *cobra.Command {
 	f.StringVar(&i.serviceAccount, "service-account", "", "name of service account")
 
 	f.StringVar(&i.opts.NodeSelectors, "node-selectors", "", "labels to specify the node on which tiller is installed (app=tiller,helm=rocks)")
-	f.StringVarP(&i.opts.Output, "output", "o", "", "skip installation and output tiller's manifest in specified format (json or yaml)")
+	f.VarP(&i.opts.Output, "output", "o", "skip installation and output tiller's manifest in specified format (json or yaml)")
 	f.StringArrayVar(&i.opts.Values, "set", []string{}, "set values for the Tiller Deployment manifest (can specify multiple or separate values with commas: key1=val1,key2=val2)")
 
 	return cmd
@@ -195,7 +194,7 @@ func (i *initCmd) run() error {
 		if body, err = installer.DeploymentManifest(&i.opts); err != nil {
 			return err
 		}
-		switch strings.ToLower(i.opts.Output) {
+		switch i.opts.Output.String() {
 		case "json":
 			jsonb, err := yaml.ToJSON([]byte(body))
 			if err != nil {
diff --git a/cmd/helm/installer/options.go b/cmd/helm/installer/options.go
index 81dd22743..0e65d72d8 100644
--- a/cmd/helm/installer/options.go
+++ b/cmd/helm/installer/options.go
@@ -77,7 +77,7 @@ type Options struct {
 	NodeSelectors string
 
 	// Output dumps the Tiller manifest in the specified format (e.g. JSON) but skips Helm/Tiller installation
-	Output string
+	Output outputFormat
 
 	// Set merges additional values into the Tiller Deployment manifest
 	Values []string
@@ -112,3 +112,28 @@ func (opts *Options) valuesMap(m map[string]interface{}) (map[string]interface{}
 	}
 	return m, nil
 }
+
+type outputFormat string
+
+func (f *outputFormat) String() string {
+	return string(*f)
+}
+
+func (f *outputFormat) Type() string {
+	return "outputFormat"
+}
+
+const (
+	fmtJSON outputFormat = "json"
+	fmtYAML              = "yaml"
+)
+
+func (f *outputFormat) Set(s string) error {
+	for _, of := range []outputFormat{fmtJSON, fmtYAML} {
+		if s == string(of) {
+			*f = of
+			return nil
+		}
+	}
+	return fmt.Errorf("unknown output format %q", s)
+}