Help uses Short message if Long is not available

command.go

@@ -248,7 +248,7 @@ func (c *Command) HelpTemplate() string {
 	if c.HasParent() {
 		return c.parent.HelpTemplate()
 	} else {
-		return `{{.Long | trim}}
+		return `{{with or .Long .Short }}{{. | trim}}{{end}}
 {{if or .Runnable .HasSubCommands}}{{.UsageString}}{{end}}
 `
 	}