Introducing UNIX and Linux

Getting started

Overview
Using UNIX
      Usernames
      Logging in
Logging out
Commands
      Typing in commands
      Commands and options
Communication with other users
      Email
      Other communication facilities
Files
      The editor Vi
            Vi commands (command mode)
            Vi commands (colon mode)
      Other editors
Input and output
      Scripts
      Here-documents
      Pipes
      Making copies of input and output
      Pagers
Emergencies
Getting help
Summary
Exercises

Logging in

Once you have found a terminal, or you have set up your own Linux machine, you are in a position to use the system. Sit down and make yourself comfortable. Make sure you can see the screen clearly and that you can reach the keyboard easily. Not only can an awkward body posture be uncomfortable, it can be dangerous, contributing to RSI (Repetitive Sprain Injury), if held for more than short periods of time.

Check that your computer is turned on - you may need to press the Return key since some computers darken their screens, or run a screensaver, after a period of inactivity. Adjust the screen's brightness so that it is at a comfortable level. Somewhere on the screen you will see the line

login:

If your computer has a graphics terminal with windows, use the mouse to ensure that the cursor is within the window containing the login: message. Now type in your username followed by Return. The computer will then print on the screen the message

Password:

and you should then type in your password. What you type in as the password will not appear on the screen, for obvious security reasons. If there are other people in the same room as you, be discrete when typing in the password, and make sure no-one is standing looking over your shoulder. If you make a mistake typing in your username or password, don't worry - you'll be given another chance. If you forget your password, your system administrator can allocate you a new one.

Be careful when you type that you distinguish between upper-case and lower-case letters - UNIX treats them as different. If your username is chris, and you enter Chris at the login: prompt, the system will not allow you to log in.

Most UNIX systems appear different to their users in many superficial ways. For instance, types of computer display will vary. The messages displayed on the screen when you log in to the system can be changed. If you are using a UNIX system at a University or College, it is likely that a document is produced by your institution to explain how to use the UNIX machines, and you should consult that document. It will clarify differences (if any) between your UNIX system and the standard version described here.