Unix Tutorial

What is Unix?

Getting started

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vi Commands

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Starting to use Unix

Logging In||Exit ||Password

To ensure security and organization on a system with many users, UNIX machines employ a system of user accounts. The user accounting features of UNIX provide a basis for analysis and control of system resources, preventing any user from taking up more than his or her share, and preventing unauthorized people from accessing the system.

Logging in :

Logging in to a UNIX system requires two pieces of information: A username, and a password. When you sit down for a UNIX session, you are given a login prompt that looks like this:

Type your username at the login prompt, and press the return key. The system will then ask you for your password. When you type your password, the screen will not display what you type.

Username

Your username is assigned by the person who creates your account. Your username must be unique on the system where your account exists since it is the means by which you are identified on the system.

Password

When your account is created, a password is assigned.

Password

The first thing you should do is change your password, using the passwd utility.For computer science department ,you must first telnet to zeus server.Once you are at zeus prompt, type the command passwd after you have logged in. The system will ask for your old password, to prevent someone else from sneaking up, and changing your password. Then it will ask for your new password. You will be asked to confirm your new password, to make sure that you didn't mistype. It is very important that you choose a good password, so that someone else cannot guess it.

Here are some rules for selecting a good password:

· Do not use any part of your name, your spouse's name, your child's name, your pet's name, or anybody's name.

· Do not use any backward spellings of any name, either.

· Do not use an easily-guessable number, like your phone number, your social security number, your address, license plate number, etc. Do not use any word that can be found in an English or foreign-language dictionary.

· Do not use all the same letter, or a simple sequence of keys on the keyboard, like qwerty.

· Do use a mix of upper-case and lower-case letters, numbers, and control characters.

· Do use at least six characters. If you have accounts on multiple machines, use a different password on each machine.

· Do not choose a password that is so difficult to remember that you must write it down.

C&IT's Useful Guidelines

Exit

When you're ready to quit, type the command exit Before you leave your terminal, make sure that you see the login prompt, indicating that you have successfully logged out. If you have left any unresoved processes, the UNIX system will require you to resolve them before it will let you log out. Some shells will recognize other commands to log you out, like "logout" or even "bye".