修复死循环问题

CMD/CMDHelper.cs

@@ -24,7 +24,7 @@ namespace LJLib.Cmd
 
                 string rslt = string.Empty;
                 line = p.StandardOutput.ReadLine();
-                while (line != "exit")
+                while (!string.IsNullOrEmpty(line) && line != "exit")
                 {
                     if (string.IsNullOrEmpty(rslt))
                     {