private void SearchBook(string command) { IEnumerable <Book> books = null; if (HasParameters(command)) { books = booksManager.FindAll(); } else { var toSearch = SubstringAfterFirstSpace(command); books = booksManager.FindByTitle(toSearch); output.PrintLine(books.Any() ? $"Found: '{toSearch}'" : $"'{toSearch}' title not Found"); } Print(books); }