diff --git a/README.md b/README.md
index 7b61982..ba60d75 100644
--- a/README.md
+++ b/README.md
@@ -18,12 +18,28 @@
 
 ## Install
 
+Homebrew:
+
+```sh
+brew install thames-technology/tap/apigen
+```
+
+Go:
+
 ```sh
-# TODO
+go install github.com/thames-technology/apigen
 ```
 
 ## Getting started
 
+Create standard `BookService` definition with `author` parent resource in `proto/bookservice/v1alpha1/service.proto`:
+
+```sh
+apigen proto -r book -p author -pkg bookservice.v1alpha1 -w
+```
+
+Create standard `AuthorService` definition without a parent resource in `proto/authorservice/v1alpha1/service.proto`:
+
 ```sh
-apigen proto -r book -pkg bookservice.v1alpha1
+apigen proto -r author -pkg authorservice.v1alpha1 -w
 ```
diff --git a/internal/template/template.go b/internal/template/template.go
index 5d39cc3..b8c7c8b 100644
--- a/internal/template/template.go
+++ b/internal/template/template.go
@@ -2,6 +2,7 @@ package template
 
 import (
 	"embed"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -28,14 +29,18 @@ type ProtoData struct {
 	Package   string
 }
 
-func Write(data *ProtoData, outDir string) error {
-	tmpl, err := template.New("proto").Funcs(funcs).ParseFS(tmplFS, "service.tmpl")
-	if err != nil {
-		return err
+type WriteOpts struct {
+	OutDir string
+	Write  bool
+}
+
+func Write(data *ProtoData, opts *WriteOpts) error {
+	if !opts.Write {
+		return writeTo(os.Stdout, data)
 	}
 
 	// Construct the output file path
-	outFilePath := filepath.Join(outDir, strings.ReplaceAll(data.Package, ".", "/"), "service.proto")
+	outFilePath := filepath.Join(opts.OutDir, strings.ReplaceAll(data.Package, ".", "/"), "service.proto")
 
 	// Create the directory structure if it doesn't exist
 	if err := os.MkdirAll(filepath.Dir(outFilePath), 0755); err != nil {
@@ -49,5 +54,14 @@ func Write(data *ProtoData, outDir string) error {
 	}
 	defer outFile.Close()
 
-	return tmpl.ExecuteTemplate(outFile, "service.tmpl", data)
+	return writeTo(outFile, data)
+}
+
+func writeTo(w io.Writer, data *ProtoData) error {
+	tmpl, err := template.New("proto").Funcs(funcs).ParseFS(tmplFS, "service.tmpl")
+	if err != nil {
+		return err
+	}
+
+	return tmpl.ExecuteTemplate(w, "service.tmpl", data)
 }
diff --git a/internal/template/template_test.go b/internal/template/template_test.go
index 46dd22e..9dd0f26 100644
--- a/internal/template/template_test.go
+++ b/internal/template/template_test.go
@@ -10,11 +10,12 @@ import (
 )
 
 func TestWrite(t *testing.T) {
+	expectedDir := "../../proto"
+
 	tests := []struct {
-		name        string
-		data        *ProtoData
-		outDir      string
-		expectedDir string
+		name string
+		data *ProtoData
+		opts *WriteOpts
 	}{
 		{
 			name: "Test Book Service",
@@ -25,8 +26,7 @@ func TestWrite(t *testing.T) {
 				Parents:   "authors",
 				Package:   "bookservice.v1alpha1",
 			},
-			outDir:      "testdata",
-			expectedDir: "../../proto",
+			opts: &WriteOpts{Write: true, OutDir: "testdata"},
 		},
 		{
 			name: "Test Author Service",
@@ -35,26 +35,25 @@ func TestWrite(t *testing.T) {
 				Resources: "authors",
 				Package:   "authorservice.v1alpha1",
 			},
-			outDir:      "testdata",
-			expectedDir: "../../proto",
+			opts: &WriteOpts{Write: true, OutDir: "testdata"},
 		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			// Ensure the output directory exists
-			if err := os.MkdirAll(tt.outDir, 0755); err != nil {
+			if err := os.MkdirAll(tt.opts.OutDir, 0755); err != nil {
 				t.Fatalf("Failed to create output directory: %v", err)
 			}
 
 			// Run the Write function
-			if err := Write(tt.data, tt.outDir); err != nil {
+			if err := Write(tt.data, tt.opts); err != nil {
 				t.Fatalf("Write() error: %v", err)
 			}
 
 			// Compare the output file with the expected file
-			outputFile := filepath.Join(tt.outDir, strings.ReplaceAll(tt.data.Package, ".", "/"), "service.proto")
-			expectedFile := filepath.Join(tt.expectedDir, strings.ReplaceAll(tt.data.Package, ".", "/"), "service.proto")
+			outputFile := filepath.Join(tt.opts.OutDir, strings.ReplaceAll(tt.data.Package, ".", "/"), "service.proto")
+			expectedFile := filepath.Join(expectedDir, strings.ReplaceAll(tt.data.Package, ".", "/"), "service.proto")
 
 			output, err := os.ReadFile(outputFile)
 			if err != nil {
@@ -71,7 +70,7 @@ func TestWrite(t *testing.T) {
 			}
 
 			// Clean up the output directory
-			os.RemoveAll(tt.outDir)
+			os.RemoveAll(tt.opts.OutDir)
 		})
 	}
 }
diff --git a/main.go b/main.go
index 2c1a0a7..5776f2e 100644
--- a/main.go
+++ b/main.go
@@ -53,6 +53,11 @@ func main() {
 						Usage:   "The directory to write the proto files to",
 						Value:   "proto",
 					},
+					&cli.BoolFlag{
+						Name:    "write",
+						Aliases: []string{"w"},
+						Usage:   "Write the output to a file",
+					},
 				},
 				Action: func(c *cli.Context) error {
 					resource := c.String("resource")
@@ -75,7 +80,12 @@ func main() {
 						Package:   c.String("package"),
 					}
 
-					return template.Write(data, c.String("out-dir"))
+					opts := &template.WriteOpts{
+						OutDir: c.String("out-dir"),
+						Write:  c.Bool("write"),
+					}
+
+					return template.Write(data, opts)
 				},
 			},
 		},