var path = Directory.GetFiles(@".idea", "workspace.xml", SearchOption.AllDirectories).First(); const string findStr = """ "keyToString": { """; const string replaceStr = """ "keyToString": { "rider.code.cleanup.on.save": "true", """; var content = File.ReadAllText(path); if(content.Contains("rider.code.cleanup.on.save")){ Console.WriteLine("alreay added"); return; } content = content.Replace(findStr, replaceStr); Console.WriteLine(content); File.WriteAllText(path, content);