First look at our one of our Liunx systems

2 primary student Linux systems.

hopper.cs.niu.edu and turing.cs.niu.edu.

This means you should be able to log into either.

provides web page storage/access
Virtual names
• faculty.cs.niu.edu
• students.cs.niu.edu
• courses.cs.ni.edu

  Additionally, a symbolic link in your home directory on hopper/turing provides direct access to your web page storage area on babbage.

login as: z912730 z912730@hopper.cs.niu.edu's password: The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. No mail. Last login: Sun Aug 23 09:00:21 2015 from adsl-108-69-163-116.dsl.emhril.sbcglobal.net z912730@hopper:~$

except maybe for the "Last Login:" message.

Terminal - terminal emulator.
  Input : keyboard
    Line focused input. 
    Only current line is active.

    Command [and options and arguments] typed on line. 
    * special delimiters allow multiple command to be entered.

    Press [enter] to feed command and arguments to command interpreter.

    Command may retrieve further input from keyboard 

      Or

    read additional input from a file via the redirection mechnanism

      Or

    read additional input from another command via the piping mechanism.

  Output : emulator window
    Command sequence may stream output to screen. 
    * Utilities are available to parse into browseable screens. 
    * e.g  less 

      or

    via redirection, store output in named file rather than on screen

      or

    via piping, channel output to the next command on the command line.

  Graphical interfaces available using X protocol. e.g geany
  

On our system, the default command interpreter is bash

  Line prompt is $

  The line prompt can be reconfigured.
    see PROMPTING in the bash man-page.
 
  Cursor prompt is a highlighted box, indicates current position on line. 

  bash provides a number of mechanisms to make input process
    friendlier. 

  [<-] and [->] cursor keys allow user to move back and forth over 
    entered characters on current command line.

  The up and down cursor keys will scroll through history list of previously 
    entered command lines.

  [ctrl]h and [backspace] deletes by pulls anything under the cursor prompt 
    to the left. *

  [del] deletes anything under the cursor. *

  * These can be modified both with the PuTTY configuration and with the
    Unix stty command. 

  Some additional [ctrl] characters availble :
 
  [ctrl]w - delete to beginning of previous word. 
    Drags character under cursor and rest of line back. 

  [ctrl]u - delete to beginning of line. 
    Drags character under cursor and rest of line back. 
    Often used from end of line to clear line.  
    * [ctrl]u works on login password entry even though the typed password
      is not displayed.

  [ctrl]y - puts back what [ctrl]u or [ctrl]w deleted. If cursor prompt
    moved, this recover will be at the new cursor position.

  [ctrl]v - allows user to enter another control character on the line 
    as a character.


  * A running program or command is referred to as a process. 
  * Processes can run in the foreground or background.
  * The following works on a program running in the foreground.

  [ctrl]c - used to signal interrupt to a foreground process.
    In most cases, program terminates. 

  [ctrl]d - signals end of file or input to a foreground process when it is 
    reading input from keyboard. 
    [ctrl]d can be used to log out.
      This can be blocked by setting the IGNOREEOF variable.

  [ctrl]s - suspend output of foreground process. Most modern systems are 
    so fast that this is not practical, use less instead.
    Accidentally entering this, will cause your terminal to appear as if 
    it is locked up.

  [ctrl]q - complement of [ctrl]s, resumes output of foreground process.
    If your terminal screen appears frozen, start with entering [ctrl]q before
    panicing. :)

  [ctrl]z - suspends but does not terminate a foreground process. 
    Use fg to restart the process in the foreground  
      or 
    bg to restart the process in the background.


bash supports command line editing with either :
  the emacs (default) or vi editor.

To use vi, issue the command set -o vi. 
This can be placed in one of the bash configuration files.

We will look at vi and less later.

Logging out

Several ways to log out cleanly

logout

exit

[ctrl]d

*The IGNOREOF variable can be set to ignore EOF from the prompt. This can
be useful to prevent accidential logouts when issuing several [ctrl]Ds.

Use logout to log out of your account.

Logging out may or may not close the PuTTY windows. You can configure PuTTY
to close on exit.

Run PuTTY and load the system configuration you wish to modify. Don't Open.

Near the bottom right of the PuTTY configuration window, you will see

  Close window on exit:
  ( ) Always  ( ) Never  (x) Only on clean exit

Select the one you want, most likely Always or Only on clean exit.

Resave the configuration and Open session.