Download Mod1: Chapter 1 (and a little extra)

Module 1
Introduction to UNIX/Linux
Chapter 1 (and a little extra)
UNIX Operating System I
Objectives
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Review of Basic Computer Terminology
What is an Operating System?
Why UNIX?
History of Unix
Different Versions
Linux
Problems with UNIX
Different Versions Note
UNIX Operating System I
Objectives (cont.)
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Features of Linux (UNIX)
Let’s Get Started!
– PuTTY
– Unix Account
– Logged In
– The Shell
– Prompts
– Commands
UNIX Operating System I
Review of Basic Computer Terminology
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Please read the “Review of Basic
Computer Terminology” under the
extra resources area.
– Hardware
– Software
– Operating System
– Programming Languages
UNIX Operating System I
What is an Operating System?
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Windows 98, Windows NT, Windows XP
– These are all operating systems
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Solaris, HP-UX, Linux
– These are all different versions of UNIX
– These are all operating systems
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Definition: A program that acts as a middle
man between the user (you) and the
hardware (the computer). It manages your
computer’s resources (the disks,
applications, loading applications, etc…)
UNIX Operating System I
Why UNIX?
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Portable Operating System
– Runs on many different machines (from
desktop PCs to high end mainframes/servers)
– Hardware Independent.
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Open Source OS
– Source Code is Free
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Powerful Internet and Network
Capabilities
Based on Standards
Large selection of high-end applications
– Many for scientific and industrial companies
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Powerful and Stable Operating System
UNIX Operating System I
History of Unix (1)
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Bell labs and other companies had a joint
venture in the 60s to develop a new OS, one of
the first multi-user operating systems.
– Ken Thompson and Dennis Ritchie developed earliest
version
– This first OS was called Multics
– Was large and slow and not quite what they wanted
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Using what they learned, they created a new
OS – UNIX (UNIX is a play on words on multics)
– What we call AT&T System V flavor.
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Offered UNIX to universities. UC at Berkeley
made some changes and came up with their
own flavor of UNIX
– What we call the Berkeley BSD flavor.
UNIX Operating System I
History of Unix (2)
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There were now two flavors of UNIX
– System V
– BSD (based on Berkeley’s changes)
– NOTE: Flavors are very similar, but do have
differences in some commands, etc…
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Companies who wanted to have Unix
run on their computers had to choose
from one of the two flavors, change it up
for their particular hardware, and sell it
with their hardware.
UNIX Operating System I
Different Versions
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IBM’s version – AIX
SUN’s version – Solaris
HP’s version – HP-UX
UNIX is a generic term. If someone is
using UNIX, we always have to ask
“What version” or “from what vendor”,
etc…
Too many different versions from too
many vendors has hurt Unix, for
reasons we will mention shortly.
UNIX Operating System I
Linux
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Free version of Unix designed to run,
among other things, on Intel based
PCs
Developed by Linus Torvalds at the
University of Helsinki in Finland.
– Linux comes from his name - Linus
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Many versions of Linux are out there.
We are using Red Hat Linux.
UNIX Operating System I
Problems with UNIX
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Remember, we mentioned that the OS is
responsible for loading applications.
When a software company writes a program
they have to write it for a particular OS. They
may choose to write it for Windows 98, or
MacOS (Macintosh computers), or Unix, or all.
If I were writing software for the home user, I
would write it for Windows. Why? I like Unix
better but I realize that there is a larger market
of users running Windows at home.
UNIX Operating System I
Different Versions Note
– How different is each version (Sun’s vs. HPs vs.
IBM’s vs. Linux)?
• Not that much anymore, since they are all based on
similar standards.
– However, some systems might have “extra”
commands they have added.
• As a user you might see some differences, but the
base commands should all be the same. I will try to
point out some differences between Solaris and Linux
as the semester goes on.
• There are, however, internal differences, which might
effect programmers.
• And of course, there are many differences in
installation, which effect Unix administrators.
UNIX Operating System I
Features of Linux (UNIX)
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The obvious: multiuser and multitasking
Portable. Written
primarily in C
language.It can be
changed up slightly to
work on different
hardware (which is
why we have so many
versions from the
different companies)
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Hierarchical Filesystem:
Similar to layout of
files/folders on PCs (but
yet very different)
Device-Independent
Input and Output: UNIX
input/output devices
(printers , disks, etc…)
are treated as files.
The Shell: The
command line interface.
The shell accepts
commands and makes
sure they are carried
out.
UNIX Operating System I
Let’s Get Started!
– We will all be using OUR Unix server
called redhat9 (its IP address is
192.168.4.21)
• Review (hopefully): every machine is known
by their IP address. The name/domain-name
(redhat9) is just for our benefit.
UNIX Operating System I
PuTTY
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We will be using the PuTTY program to
connect to the UNIX server.
On your PC:
– Copy the PuTTY program to your desktop.
– Double Click on PuTTY.
UNIX Operating System I
PuTTY Screen
UNIX Operating System I
PuTTY: Example of Login (graphic)
Note: Enter your UNIX account at the login prompt shown above then press Enter.
UNIX Operating System I
PuTTY: Example of Password (graphic)
Note: Next enter your password and then press Enter.
UNIX Operating System I
PuTTY: If you have an error you will have
to re-enter password.
Note: If you get “Access denied” then it will prompt you to re-enter
password again.
UNIX Operating System I
Unix Account
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Your UNIX account and password will be
the same as the account/password you
received during in class.
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After you enter your login account, press
return and enter your password.
– If you make an error while entering your
password, try to erase and start over. If that
doesn’t work, you will be prompted to re-enter.
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Password will not echo at the prompt.
UNIX Operating System I
Logged In
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After you successfully log in you will see:
– Some welcome messages
– The unix shell prompt (shown below):
[terry@redhat9 terry]
UNIX Operating System I
The Shell
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The shell prompt tells you that UNIX is waiting
and ready for you to enter a UNIX command:
– date
date is the
command
entered
[terry@redhat9 terry]$
is the prompt
You could enter another
command at this prompt
UNIX Operating System I
Prompts (1)
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Prompts can have many forms:
$
bash-2.05$
%
Hello%
In our class, whenever you see the $ in
notes or directions, that will refer to your
prompt (unless otherwise instructed).
Remember, your prompt for now is:
[username@redhat9 home]$
UNIX Operating System I
Prompts (2)
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When you see a prompt, enter a
command (and then press enter)
$ date
$ who
$ cal
As shown above, “date” and “who”
and “cal” are all commands that can
be entered at the prompt.
– Remember, you type in the “date” not
the “$”.
UNIX Operating System I
Prompts (3)
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I know this sounds silly, but if you do
not see a prompt, then you cannot
type in a new command.
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If you ever get stuck, and want to
break out of the command you
entered and start over, press the
[Ctrl][c] keys on your keyboard at
the SAME TIME.
UNIX Operating System I
Commands (1)
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Commands can be as simple as one word,
two words, or many words together.
The following are all UNIX commands:
$ date
$ ls
$ ls –la x*
$ tar –cvf text x*
$ who
$ cal
UNIX Operating System I
Commands (2)
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Review: Whenever I want you to enter
a command, I will probably use the
following notation:
$ cal
– DO not type the $. That represents the
prompt. The above example means I
want you to type: cal
UNIX Operating System I
Commands (2)
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There are many commands
discussed in each chapter. We will not
be covering all of those commands.
UNIX Operating System I
The End
Please make sure and review
learning module and textbook
for more information on
module 1.
UNIX Operating System I