Add help output

tesseract/genconf/main.go

@@ -131,7 +131,7 @@ func main() {
 
 	args := flag.Args()
 	if len(args) == 0 {
-		showConfig(*configFile)
+		showHelp()
 		return
 	}
 
@@ -142,6 +142,7 @@ func main() {
 		generateEnv(*configFile)
 	default:
 		fmt.Fprintf(os.Stderr, "Unknown command: %s\n", args[0])
+		showHelp()
 		os.Exit(1)
 	}
 }
@@ -160,6 +161,19 @@ func loadConfig(yamlFile string) Config {
 	return config
 }
 
+func showHelp() {
+	fmt.Printf("Usage: %s [options] <command>\n\n", os.Args[0])
+	fmt.Printf("Options:\n")
+	fmt.Printf("  -c <file>    Path to YAML configuration file (default: ./tesseract-staging.yaml)\n\n")
+	fmt.Printf("Commands:\n")
+	fmt.Printf("  gen-html     Generate index.html and log.v3.json files in each log's localdirectory.\n")
+	fmt.Printf("               Creates HTML pages with log information and CT log metadata JSON.\n")
+	fmt.Printf("               Computes LOG_ID and public keys from private keys.\n\n")
+	fmt.Printf("  gen-env      Generate .env files and combined roots.pem in each log's localdirectory.\n")
+	fmt.Printf("               Creates TESSERACT_ARGS environment variable with command line flags.\n")
+	fmt.Printf("               Combines global roots and log-specific extraroots into roots.pem.\n\n")
+}
+
 func showConfig(yamlFile string) {
 	config := loadConfig(yamlFile)