Welcome to UNIX
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Overview: This tutorial gets you started in UNIX, explaining some of the
basic terms such as usernames and account, some procedures like
how to log in and how to log out, and how to use the help
system. It also talks a bit about ethical uses of computers.
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Section Topics
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Accounts and users
Logging in and out
What is UNIX? What are operating systems?
Proper use of your account (ethical and legal restrictions)
Accounts and users
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To use UNIX, you need an account on the computer which your instructor will give
you. Each account has an account name and an account number. Sometimes the
account name is called your username. At Canisius, most usernames are the
last name of the student, or part of the last name (since there is a length
limit on usernames). You do not need to worry about your account number since
that is internal to UNIX and you never need to type it in. Somebody who has an
account in UNIX is called a user.
Each account is protected by a password of your choosing. Since your password
is the primary security tool, it should not be something which others can guess.
It should contain at least 7 characters, including one number.
DO NOT use names of pets, relatives, your middle name, your street address,
your type of car or anything obvious. In fact, your password should not even
be an English word at all, which is why inserting a number is useful.
Here's a good example:
fluf7fy8
Fluffy may be the name of the user's pet cat, but the digits will fool people
who try to crack the password by guessing that the user used her pet's name.
Logging in and out
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In order to login you must first connect to the UNIX computer. There are two
ways to do this: from a terminal or personal computer at Canisius, or from
home. If you are at Canisius, you just turn on the terminal and press RETURN
a few times until you see
cisco2>
If you are using a personal computer like a Macintosh or an MS-DOS machine,
you have to start the appropriate program that connects to another computer.
If you are at home, you have to turn on your modem and dial into the school's
computer, and, once connected, press RETURN repeatedly until you get the
cisco2> prompt. (A separate tutorial discusses dialing in from home in more
detail.)
In all cases, you will connect to a special intermediary called a terminal
server, which is just a small, special purpose computer. The name of the
terminal server we use is called Cisco 2 and it has its own prompt
cisco2>
Type the name of the main UNIX computer, which is niktow, and press return.
cisco2> niktow
Then you will get the actual UNIX login prompt, which looks like
login:
Type your username and press RETURN. If you make a mistake, you may use the
delete key. Or if you "screw up", just press RETURN and try again.
Next, type in your password. It will not echo to the screen. Press RETURN
once you've typed your password and, if it was correct, you will see various
login messages.
Eventually, you should see what is called a "shell prompt", signifying that
you've passed the many hurdles and are now logged on and ready to use UNIX.
The shell prompt for new UNIX users at Canisius is
niktow 101 %
At other places, it may be a dollar sign or just a single percent sign, or
many other symbols. Such things are customizable. For purposes of
illustration in this guide, the single percent sign will be used as the prompt.
To log out, simply type the command "logout" and press RETURN.
% logout
What is UNIX? What are operating systems?
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Bare computer hardware isn't very interesting or useful without software
(programs) to run on it. Likewise, most software requires the support of a
lot of subsidiary software. This subsidiary software is collectively called
an "operating system". An example of one of the services UNIX provides is a
file system that provides directories, files, and a number of operations by
which they can be accessed.
Every modern computer, whether a personal micro or a supercomputer, uses an
operating system. Most computers can run several different operating systems,
though not usually at the same time. Different companies create their own
operating systems, or they provide a variant of a popular one, like UNIX.
It might be helpful to list the major operating systems in use today. IBM
mainframes often run one of two systems: MVS or VM/CMS. These systems are
large, highly developed and sophisticated and almost never run on anything
other than large IBM computers.
Digital Equipment Corporation (DEC) is still marketing their popular operating
system VMS. Notice that MVS and VMS are very similar in initials, which is no
accident. MVS stands for Multiple Virtual System and VMS is Virtual Memory
System. These all refer to the main features which the operating systems made
popular about 20 years ago. VMS almost always runs on DEC minicomputers,
which are medium size systems costing about $10,000 to $500,000. These are
seldom used as personal computers, but rather as networked computers shared by
many users in a company.
In the world of micro or personal computers, there are two main operating
systems: System 7 for Macintoshes and MS-DOS for IBM PCs and IBM PC-clones. In
fact, most personal computers that contain an Intel x86 chip (286, 386, 486, and
Pentium) run MS-DOS. The Macintosh operating system was, up until recent times,
simply called "The System".
That leaves UNIX. UNIX is really a generic term, since there are hundreds of
similar operating systems. Most of these systems have an X in their names,
such as AIX, HP/UX, AUX, Xenix, Linux, and so on. A few companies have a
version of UNIX whose name does not give away its lineage, such as SUN
Microsystems' SUNoS, now renamed Solaris, which is still a variant of UNIX.
The history of UNIX and the reasons for its success are long and complex, and
are explained in the history tutorial.
Proper use of your account (ethical and legal restrictions)
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THE FOLLOWING IS VERY IMPORTANT. There are certain ethical and legal
responsibilities that accompany your UNIX account. For a full description,
please read the Computer Science Handbook or consult with a faculty member.
You will be held liable for anything done with your account, so do not lend
it to anyone nor let your password be known. If you allow someone to use your
account and that person commits a crime, you may be held responsible too.
Also, do not attempt to use your account to break into other computers, send
electronic hate mail, harass other users, spy on people, steal software or
files, or in short do anything that violates the law and general rules of
good behavior. These are serious responsibilities! Please do not take them
lightly!
Traditionally, UNIX has flowered in a relaxed atmosphere of academicians
(people who teach and work in colleges and universities) and some small
companies. Most of the people in these places felt a certain kinship in using
UNIX and very few took advantage of its relatively insecure nature.
However, with UNIX being used almost everywhere and by a wide variety of people,
some unscrupulous computer users are now exploring its weaknesses. They exploit
holes in UNIX security to invade the privacy of others, steal other users' work,
or interfere with others' access to shared resources. Some claim to do this
only for the thrill involved but the effect is the same. Thus, it becomes
necessary to protect rightful users and their work. This involves using pass-
words and encryption, formulating ethical codes and new laws, and taking legal
action to enforce the laws and codes. Although this protects users, it
restricts access to the resources, costs time and money, and creates a hostile
atmosphere. Please avoid unethical activity - it takes all the fun out of
education.
For a detailed description of the code of ethics for the Computer Science
Department read the section on ethics in the main menu of this help system or
consult the departmental handbook. If you are in doubt about any activity not
covered in the handbook, feel free to ask your professor.
At Canisius, ITS (also called "the Computer Center") has a code of conduct that
you are obliged to follow if you use any of the microcomputers on campus that
they manage. These include all the Macintoshes and IBM-PC clones and all the
equipment in the public labs.