01

Programming Methods and Techniques I
Introduction to UNIX System
Andrzej Głowacz, Ph.D.

2010-10-04

Task 1 Starting Kubuntu Linux

1. Start with turning your computer on. Then choose operating system Kubuntu to boot up. Kubuntu will start

boot program.

2. Next the system kernel and hardware drivers will be loaded. After system is ready to work, you will see

graphic environment KDE. Type following URL address in browser:

http://eit.agh.edu.pl/spe/PMaTI_en

.

Read all published documents: a) course rules, b) lectures and c) laboratory instructions.

Task 2 Using Konsole

1. In the system taskbar select and click Konsole shortcut - it is located in Start > System > Konsole (icon

displaying terminal screen).

2. After console is started you will see window with prompt message

ubuntu@ubuntu:~$

3. This notation means that you are logged as user „ubuntu”, into operating system „ubuntu”, and working

directory is tilde („~”). Tilde is general shortcut to your home directory. In this case you are logged in local
system and storage system is located on local hard disk. Note that Kubuntu is specific version of Ubuntu
Linux.

Task 3 Linux commands

1. There are many commands and combinations of them in UNIX system. This is advantage for programmers

and UNIX systems are commonly used for advanced tasks. A command consists of its name, options and
parameters, which can be typed in console window.

command [options] [parameters]

2. Option (or switch) is a sequence of characters usually starting with “-“. It defines various behavior of the

same command. For example,

ls

command will print files in working directory, whereas command with

option

ls –l

will print additional information.

3. Parameters (or arguments) define objects of command operation. For example,

ls –l Desktop

in Kubuntu

will print the content of directory Desktop. Let us notice, that command is mandatory, whereas options and
parameters are not required (we write it with square brackets []).

4. Basic commands are:

ls

prints files in directory;

uname –a

prints information about system;

date

prints

local time,

pwd

prints working directory.

Task 4 Using documentation

1. Most commands are well-documented in UNIX system. Manual pages for specified command can be

displayed by typing

man command

. For example,

man ls

(notice that ls is parameter for command man)

prints manual for a command ls. You can move across man pages with

Page down - combination of "^V" (CTRL+V) or space,

Page up – combination of "^B" (CTRL+B),

"/" –search,

"Q" - quit.

2. For some commands, documentation can be displayed with

info command

, e.g.

info type

.

3. Some commands prints a short usage description after typing

command --help

, e.g.

ls --help

. There are

additional possibilities:

whatis command

prints brief command description,

whereis command

prints

command and manual localization,

type command

prints type of the command.

4. For search keyword in the whole documentation, there is command

apropos keyword

. This prints pages,

where keyword is found.

Task 5 Users

1. UNIX users are divided into groups of different privileges. Users and groups are created by superuser (root).

Each user has its own ID number, which can be checked with command

id

.

2. There can be many users logged in remotely at the same time and each user can have concurrent sessions.

List of logged users can be checked with one of the following commands:

who

,

w

,

finger

. The difference here

is in options and results. For example,

finger user

prints following information about user: username,

home directory, login status, mail status, plan file, name, surname and default shell. Shell is a program
interpreting the commands. Common shells are: bash (GNU Bourne-Again SHell) and tcsh (T C-like syntax
SHell).

3. Users run programs, which create processes in machine’s memory. List of executed processes can be

checked with command

ps

, or

ps -u user

for given user.

4. First and foremost, active process is shell (and ps – when it is run). Useful information is PID (unique

process ID), TTY (terminal which run process), running time and process name.

Task 6 Logging into remote system (student.uci.agh.edu.pl)

1. We want to connect to remote host named student.uci.agh.edu.pl, which is located in UCI (University Center

of Informatics). For safe login into server we use ssh (ang. Secure Shell)

ssh [e-mail]

, where user is name you received when your account was created.

2. System prompts for your password – you need to type it (password is not displayed on screen because of

security reasons)

password:

3. After successful login, you receive system information and prompt

login@student:~ (101) >

. Now you

are in terminal of remote system and all commands are related to that system.

4. Command

passwd

let you change your password in system. You need to give old password, and twice the

new one (in order to avoid typing errors). There are the same rules as during login (passwords are not
displayed). Passwords should be changed at first login or after specific time.

5. Session ends after command

logout

.

6. Command

ping server

checks, if the server is reachable in network:

ping student.uci.agh.edu.pl

.

This should be the first command in lack of connection. To check routing path, you can use command

traceroute server

.

Questions

1. Read carefully course rules. If something is unclear or you have additional questions, this is certainly the

best time to ask the lecturer.

2. If it is your first contact with UNIX, you need to learn starting and closing the system, Konqueror browser

and Konsole.

3. Get familiar with commands: man, info, ls, uname, whatis, whereis, type, apropos, id, who, w, finger, ps, ping,

ssh. Put your focus on following: a) what is the purpose of each command? b) what is the syntax? c) what are
the options? d) what are the parameters? e) what is the usability?

4. Notice the differences between local (Kubuntu) and remote (SunOS) system. Are commands the same in

both systems?

5. Download image Kubuntu Linux from

http://www.kubuntu.org

and burn it. After disc is ready, you can boot

up your computer directly from it. Try all the presented commands by yourself.