Command method dont change variables on server

Hi all! I have a strange problem. CmdStartLoad dont change longloadData, longpos.

 public string longloadData = "";
 public int longpos = 0;

 [Command]
 void CmdStartLoad()
 {
         Debug.Log("Make copy planet");
         map.Save("temp.txt"); //Its work!
         Debug.Log("Planet copied");
         StreamReader sr = new StreamReader("temp.txt");
         longloadData = sr.ReadToEnd(); //Its not work!!!
         sr.Close();
         longpos = 0; //Its not work!!!
         //longloadData is correct only in CmdStartLoad
 }

In debugging longloadData changes in CmdStartLoad, but in Update its not changes

 void Update () {
     if(longloadData.Length > 0)// longloadData = ""
         {
             string data = "";
             int i;
             for(i = longpos;i - longpos < packetSize && i < longloadData.Length;i++)
             {
                 data += longloadData[i];
             }
             RpcLongLoad(data, longpos, longloadData.Length);
             longpos = i;
             if (longpos == longloadData.Length)
                 longloadData = "";
         }
 }

Why did it happen?