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

Usernames

In order to use your UNIX system you will need a username and a password. The username is a code which will allow you to access the system, and to distinguish you from any other users. For the rest of this book, we shall assume you have been given the username chris. The password verifies that you are in fact the person allowed to use that username, and is similar to the PIN (4-digit code) of an ATM (cash machine) but longer and more secure. You should already have been told what arrangements have been made for allocating you a username. If not, you must ask your system administrator.

You will either be asked to choose a password, or you will initially be allocated one, in which case you will have the opportunity to change your password at a later time. When choosing a password, which can normally be up to eight characters long, bear in mind that you don't want anyone else to guess what it is. Some simple rules will help you. Always use a mixture of upper-case and lower-case letters, together with digits or other symbols. Always choose passwords which are eight characters long. Never choose as password a word that occurs in a dictionary, or the name of a person. If you ever think that someone has discovered your password, change it immediately and tell your system administrator. It is also good practice to get into the habit of changing your password every few weeks as a matter of routine.