public static void cmd()
 {
	 StringBuilder sb = new StringBuilder();
	 int c;
	 System.out.print("SimPL> ");
	 while(true)
	 {
		 
		 try {
			c = System.in.read();
			if(c=='$')
			{
				System.out.print("SimPL> ");
			    System.out.println(run(sb.toString()));
			    System.out.print("SimPL> ");
				sb = new StringBuilder();
			}
			else
			{
				sb.append((char)c);
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	 }
 }