1. In WinXP/Win98, choose Command Prompt to use the Dos command environment. Type the command
   telnet personal.cityu.edu.hk
2. As soon as the connection is made, The remote host login prompt will be displayed.
3. You should log in by typing your user name terminated by . Then your password when the password prompt appears.
4. Once logged in, you will see some greeting messages and a sommand prompt moscow% indicating that the system is ready to accept commands.

	moscow%passwd
	Old password:
	New password:
	Re-enter new password:
	moscow%

• the most basic file display command
  
• good only for displaying small files as it scrolls to the end
  
• for ASCII file only, but will attempt to display anything
  

                moscow% cat >  HelloWorld.java <Enter>
                public class HellowWorld {<Enter>
                   public static void main(String[] arg) {<Enter>
                      System.out.println("Hello World");<Enter>
                   }<Enter>
                }<Enter>
		<CTRL D>

• Creates new files or modifies existing files.
  
  
• 2 basic modes of operation: the command mode and the insert mode (text input mode).
  
• The key has a special meaning to vi in both modes:
  
  • command mode - cancels vi commands
    
  • insert mode - terminates insert mode
    
• Most commands are single letters.
  
  

/*               Program CirArea.Java                 	**
 **                                                     **
 ** This program asks the user to input a decimal       **
 ** number for the radius of a circle.  The program     **
 ** then calculates the area of the circle.             */

import java.io.*;

public class CirArea  {
    public static void main(String[] arg) throws IOException {
       float area ;
       int r  ;
       final float pi=3.14f ;

       System.out.println("Please enter radius in whole number: \n") ;
       r = Integer.parseInt((new BufferedReader(new InputStreamReader(System.in))).readLine());

       area = pi * r * r ;

       System.out.println("The radius you provided was " + r + " feet and  the area is about " + area + "sq feet");
     }
}