diff --git a/main.go b/main.go
index 645a420..85b2197 100644
--- a/main.go
+++ b/main.go
@@ -10,6 +10,8 @@ import (
 	"time"
 
 	"github.com/bradleyfalzon/ghinstallation"
+	"github.com/google/go-github/v52/github"
+	"github.com/k0kubun/pp/v3"
 )
 
 var (
@@ -27,6 +29,7 @@ func main() {
 	instID := flag.Int64("inst-id", 0, "Installation ID")
 	export := flag.Bool("export", false, "show token as 'export GITHUB_TOKEN=...'")
 	showVersion := flag.Bool("version", false, "show version info")
+	showInsts := flag.Bool("show-insts", false, "show all of the installations for the app")
 
 	origUsage := flag.Usage
 	flag.Usage = func() {
@@ -45,17 +48,29 @@ func main() {
 		os.Exit(0)
 	}
 
+	key := os.Getenv("GITHUB_PRIV_KEY")
+	if key == "" {
+		log.Fatal("Please populate GITHUB_PRIV_KEY environment variable with the private key for the App")
+	}
+
+	if *showInsts {
+		if *appID == 0 {
+			fmt.Fprintf(os.Stderr, "App ID is required to show the installations for the app.\n\n")
+			flag.Usage()
+			os.Exit(1)
+		}
+
+		showInstallations(*appID, []byte(key))
+
+		return
+	}
+
 	if *appID == 0 || *instID == 0 {
 		fmt.Fprintf(os.Stderr, "App ID and Installation ID are required.\n\n")
 		flag.Usage()
 		os.Exit(1)
 	}
 
-	key := os.Getenv("GITHUB_PRIV_KEY")
-	if key == "" {
-		log.Fatal("Please populate GITHUB_PRIV_KEY environment variable with the private key for the App")
-	}
-
 	// Wrap the shared transport for use with the app ID 1 authenticating with installation ID 99.
 	itr, err := ghinstallation.New(http.DefaultTransport, *appID, *instID, []byte(key))
 	if err != nil {
@@ -80,3 +95,34 @@ func main() {
 func showExport(token string) {
 	fmt.Printf("export GITHUB_TOKEN=%s\n", token)
 }
+
+func showInstallations(appID int64, key []byte) {
+	atr, err := ghinstallation.NewAppsTransport(http.DefaultTransport, appID, key)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	client := github.NewClient(&http.Client{Transport: atr})
+
+	opts := &github.ListOptions{
+		PerPage: 10,
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	for {
+		inst, resp, err := client.Apps.ListInstallations(ctx, opts)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		pp.Println(inst)
+
+		if resp.NextPage == 0 {
+			break
+		}
+
+		opts.Page = resp.NextPage
+	}
+}