Logging On and Logging Off


  • This part of using UNIX is a little bit different when using the graphical workstations, but the concepts here are important so read this section anyway.
  • UNIX is a "Time Sharing" system.
  • More than one person can use the same computer at the same time.
  • Any time-sharing system needs a way to tell one person from another.
  • UNIX uses a username to tell people apart.
  • username gets chosen for you by the "Systems Administrator" (also called "sys-admin" or "SA").
  • When nobody is logged in on a terminal, or when you are logging into a UNIX computer remotely using ssh, rlogin, etc., usually a login banner of some sort is shown.
  • Typical a login banner might look like:

    	SunOS 5.7

  • At the "login:" prompt, type your username, e.g. "kns".
  • It will now ask for your password. The screen will look like:

    	SunOS 5.7
    	login: kns

  • Type in your password. It will not be printed on the screen as you type it so that someone watching can not see it.
  • If you typed the username and password right you will now get a shell prompt which is usually just a % character on systems that have had no tailoring (most sys-admins do some tailoring).
  • If you typed your username and/or password wrong it will say "Login incorrect" and will go back to the "login:" prompt. You will need to type the username and password again.
  • Note that sometimes the keys for the numeric keypad on some computers do not default to sending the digits. They actually send other characters. So if your password has numbers in it, you might want to try using the numbers across the top of the keyboard if you are sure you are typing your username and password right but you still get "Login incorrect".
  • After a successful login, a "Message Of The Day" (MOTD) gets printed to your screen before your shell prompt.
  • Your sys-admin REALLY wishes you would read that. Your sys-admin puts important things like when the systems will be unavailable in the MOTD.
  • The shell prompt can be set to something other than %. How will be described later.
  • For all examples in this tutorial, the % will be what gets shown as being the prompt.
  • The first thing you need to know after logging on is how to log off.
  • This is done with the logout command:

    	% logout