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ASSIGNMENT 1.1: Introduction to Unix/Linux architecture, features,Unix File System.

ASSIGNMENT 1.2: Familiarization with basic Unix/Linux commands,creating a scrit.

UNIX

U!I" is an oerating system which was #rst de$eloed in the %&'(s,and has been under constant de$eloment e$er since. )y oeratingsystem, we mean the suite of rograms which ma*e the comuterwor*. It is a stable, multi+user, multi+tas*ing system for ser$ers,des*tos and latos.

U!I" systems also ha$e a grahical user interface -UI similar toicrosoft 0indows which ro$ides an easy to use en$ironment.1owe$er, *nowledge of U!I" is re2uired for oerations which aren3tco$ered by a grahical rogram, or for when there is no windowsinterface a$ailable, for examle, in a telnet session.

UNIX ARCHITECTURE

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UNIX INTERFACES

UNIX SHELL

4he shell acts as an interface between the user and the *ernel. 0hena user logs in, the login rogram chec*s the username and assword,and then starts another rogram called the shell. 4he shell is acommand line interreter 5LI. It interrets the commands the usertyes in and arranges for them to be carried out. 4he commands arethemsel$es rograms: when they terminate, the shell gi$es the useranother romt 6 on our systems.

4he adet user can customize his/her own shell, and users can usedi7erent shells on the same machine.

4he tcsh shell has certain features to hel the user inuttingcommands.

Filename 5omletion + )y tying art of the name of a command,#lename or directory and ressing the 84ab9 *ey, the tcsh shell willcomlete the rest of the name automatically. If the shell #nds more

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than one name beginning with those letters you ha$e tyed, it willbee, romting you to tye a few more letters before ressing thetab *ey again.

1istory + 4he shell *ees a list of the commands you ha$e tyed in. Ifyou need to reeat a command, use the cursor *eys to scroll u anddown the list or tye history for a list of re$ious commands.

UNIX UTILITY PROGRAMS

4here are large number of utility rograms which are classi#ed into 'categories which are

%. File and directory maniulation commands.

. Filters.

;. . System ?dministration.

'. iscellaneous.

UNIX KERNEL

Fig: ?roximate structure of -eneric Unix @ernel

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4he *ernel of U!I" is the hub of the oerating system: it allocatestime and memory to rograms and handles the #lestore andcommunications in resonse to system calls.

?s an illustration of the way that the shell and the *ernel wor*

together, suose a user tyes rm my#lewhich has the e7ect ofremo$ing the #le my#le. 4he shell searches the #le store for the#le containing the rogram rm, and then re2uests the *ernel,through system calls, to execute the rogram rmon my#le. 0henthe rocess rm my#lehas #nished running, the shell then returnsthe U!I" romt 6 to the user, indicating that it is waiting forfurther commands.

UNIX FILE SYSTEM

4he U!I" #lesystem contains se$eral di7erent tyes of #les:

Ardinary Files

o Used to store your information, such as some text you ha$ewritten or an image you ha$e drawn. 4his is the tye of #lethat you usually wor* with.

o ?lways located within/under a directory #le

o Bo not contain other #les

Birectories

o )ranching oints in the hierarchical tree

o Used to organize grous of #les

o ay contain ordinary #les, secial #les or other directories

o !e$er contain CrealC information which you would wor* withsuch as text. )asically, Dust used for organizing #les.

o ?ll #les are descendants of the root directory, named / located at the to of the tree.

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Secial Files

o Used to reresent a real hysical de$ice such as a rinter,tae dri$e or terminal, used for I/A oerations

o Unix considers any de$ice attached to the system to be a#le + including your terminal:

)y default, a command treats your terminal as thestandard inut #le stdin from which to read its inut

Eour terminal is also treated as the standard outut #lestdout to which a command3s outut is sent

o 4wo tyes of I/A: character and bloc*

o Usually only found under directories named /de$

' characters

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xtensions: may be used to identify tyes of #leslibc.a + archi$e, library #lerogram.c + 5 language source #lealha.f + Fortran source #lexwds.o + AbDect/executable codemygames. + 5omressed #le

1idden Files: ha$e names that begin with a dot . For examle:.cshrc .login .mailrc .mwmrc

Uni2ueness: as children in a family, no two #les with the samearent directory can ha$e the same name. Files located insearate directories can ha$e identical names.

Teser$ed Filenames:/ + the root directory slash. + current directory eriod.. + arent directory double eriodV + your home directory tilde

UNIX SYSTEM PATH NAMES

Secify where a #le is located in the hierarchically organized #lesystem

ust *now how to use athnames to na$igate the U!I" #lesystem

?bsolute

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cd ../2uattro + relati$e athnamecd /usr/home/2uattro + absolute athname

UNIX FILE PARENT-CHILD RELATIONSHIP

In U!I" all #les are related to each other. 4he #le system on U!I" is thecollection of all these related #les organized in a hierarchical structure.It is reresented by the following:

FILE & DIRECTORY COMMANDSDIRECTORY COMMANDS

%. wd + rint wor*ing directory. 4ells you which directory youare currently in.wd

. m*dir + ma*e directory. 0ill create the new directory in yourwor*ing directory by default.m*dir data

;. cd + change to seci#ed directory. ay secify either the

absolute or relati$e athname. cd with no athnamechanges to your home directory.cd .. + change to arent directorycd + change to home directory

=. rmdir + remo$e directory. Birectories must be emty beforeyou remo$e them. rmdir roDect%

4o recursi$ely remo$e nested directories, use the rmcommand with the +r otion:rm +r dirctoryWname

FILE COMMANDS

%. ls + lists #lesls +l + show contents of wor*ing directoryls +d + show all directory

. cat+ 4his command is useful for $iewing as well as forconcatenating hence the name CcatC #les together.

http://www.cis.rit.edu/class/simg211/unixintro/man/mkdir.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/cd.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/rmdir.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/ls.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/cat.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/cat.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/cd.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/rmdir.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/ls.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/cat.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/mkdir.txt

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cat test test% + shows contents of both #les on terminal.cat #le% #le O #le; + adds #le% and #le to ma*e #le;

;. c + coies #les. 0ill o$erwrite unless otherwise seci#ed.c samle.f samle.f + coies samle.f to samle.f

=. m$ + mo$es #les. 0ill o$erwrite unless otherwise seci#ed. ust

also ha$e write ermission in the destination directory.m$ samle.f samle.f + mo$es samle.f to samle.fm$ dir% newdir/dir + mo$es contents of directory dir% tonewdir/dirm$ X.txt chat% + mo$es all #les with .txt suYx todirectory chat%

>. date Z shows the system date.'. cat Z shows the calendar.

catNmonthO NyearO + Show calendar for the month of theseci#c year.

http://www.cis.rit.edu/class/simg211/unixintro/man/cp.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/mv.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/cp.txthttp://www.cis.rit.edu/class/simg211/unixintro/man/mv.txt

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ASSIGNMENT 2.1:

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PROCESS TO MODIFY ACCESS PERMISSIONS

E.g.Temo$e write ermissions w for all classes a, re$enting

anyone from writing to the #le:

Pls +l our)estTeferenceFile+rw+rw+r++ teamleader usguys &' ?r _ %:>;

our)estTeferenceFilePchmod a+w our)estTeferenceFilePls +l our)estTeferenceFile+r++r++r++ teamleader usguys &' ?r _ %:>;

our)estTeferenceFileE.g. Set the ermissions for the owner and the grou ug to read and

execute rx only no write ermission on referenceLib, re$entinganyone to add #les.

Pls +ld referenceLibdrwxr+++++ teamleader usguys &' ?r _ %:>; referenceLibPchmod ug^rx referenceLibPls +ld referenceLibdr+xr+x+++ teamleader usguys &' ?r _ %:>; referenceLib

VI EDITOR

4he $i editor short for $isual editor is a screen editor which isa$ailable on almost all Unix systems.

It has three oeration modes:%. 5ommand ode. Insert ode;. x ode

4he syntax used to create or oen a #le in $i editor is:

$i N#lename.extensionO

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SHELLSCRIPT PROGRAMMING

Q.0rite a menu dri$en shell rogram for erforming the followingoerations.

Cod!echo Cnter #rst number: C

read aecho Cnter second number: C

read becho Cnter an oeration ],+,X,/,6,`: C

read o

case Po in] r^Kexr Pa ] PbKHH+ r^Kexr Pa + PbKHHJX r^Kexr Pa JX PbKHH/ r^Kexr Pa / PbKHH6 r^Kexr Pa 6 PbKHH` r^Kecho CPa ` PbC bcKHHX echo CIn$alid InutC

exitHHesac

echo Pa Po Pb C^C Pr

O"#$"#!nter #rst number:(nter second number:%(nter an oeration ],+,X,/,6, :](]%(^;(

nter #rst number:(nter second number:%(nter an oeration ],+,X,/,6, :/

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(/%(^

ASSIGNMENT %: aximum G inimum number in set,

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O"#$"#!nter the number of integers:;nter the integers:(

;(%(

4he max $alue is ;(4he min $alue is %(

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%.2.0rite a shell rogram to #nd the rime numbers in a gi$en rangeof numbers.

Cod!echo Cnter the number to test:C

read numcount^end^Kexr Pnum / Krime^truewhile 8 Pcount +le Pend 9do

if 8 Kexr Pnum 6 PcountK ^^ ( 9then

rime^falsebrea*

#count^Kexr Pcount ] %Kdoneif 8 Prime ^^ true 9then

echo C4he number is rimeCelse

echo C4he number is !A4 rimeC#

O"#$"#!

nter the number to test:%

4he number is rime

nter the number to test:%

4he number is !A4 rime

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%.%.0rite a shell rogram to chec* if a gi$en number is alindrome ornot.

Cod!echo Cnter the number:C

read numtem^Pnums^(while 8 Ptem Q^ ( 9do

r^Kexr Ptem 6 %(Ks^Kexr Ps JX %( ] PrKtem^Kexr Ptem / %(K

doneif 8 Ps ^^ Pnum 9

then echo C4he number is a alindromeCelse

echo C4he number is !A4 a alindromeC#

O"#$"#!nter the number:%%

4he number is a alindromenter the number:%

4he number is !A4 a alindrome

ASSIGNMENT .1! Sum of the Series of !atural !umbers where theLimit is gi$en by the user

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Cod!

Q/bin/bash

echo +n Cnter n to calculate sum of #rst n natural numbers: C

read nsum^(fori^%HiN^nHi]]do

sum^Kexr Psum ] PiKecho +n CPi]C

doneecho +e CJb^PsumC

Output:

nter n to calculate sum of #rst n natural numbers: =%]];]=^%(

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ASSIGNMENT .2!)ubble Sort an array of user inuts

Code:

Q/bin/bash

echo +n Cnter the number of inuts: Cread nfori^(H iNnH i]]do

echo +n Cnter inut: Cread a8i9

done

fori^(H iNn+%H i]]do

forD^(H DNn+i+%H D]]do

if 8 Pa8D9M +gt Pa8D]%9M 9then

tem^Pa8D9Ma8D9^Pa8D]%9Ma8D]%9^Ptem

#done

done

echo C4he sorted array is:C Pa8X9M

Output:nter the number of inuts: >nter inut: =nter inut: nter inut: ;nter inut: 'nter inut: %

4he sorted array is: % ; = '

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ASSIGNMENT .%:5alculator from the terminal

Cod!

Q/bin/bashecho +n Cnter #rst number: Cread aecho +n Cnter second number: Cread becho +n Cnter an oeration ],+,X,/,6,`: Cread ocase Po in

] r^Kexr Pa ] PbKHH+ r^Kexr Pa + PbKHH

JX r^Kexr Pa JX PbKHH/ r^Kexr Pa / PbKHH6 r^Kexr Pa 6 PbKHH` r^Kecho CPa PbC bcKHHX echo CIn$alid InutC

exitHHesacecho Pa Po Pb C^C Pr

Output:

nter #rst number: =nter second number: nter an oeration ],+,X,/,6,`: `= ` ^ %'

nter #rst number: >>nter second number: >nter an oeration ],+,X,/,6,`: 6>> 6 > ^ (

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ASSIGNMENT .:)inary search

Cod!

Q/bin/bashecho +n Cnter the number of inuts: Cread nfori^(H iNnH i]]do

echo +n Cnter inut: Cread arr8i9

doneecho +n Cnter the number to search: C

read search insertion sortfori^%H iNnH i]]do

tem^Parr8i9MforD^i+%H DO^(H D++do

if 8 Parr8D9M +gt Ptem 9then

arr8D]%9^Parr8D9M

else brea*#

donearr8D]%9^Ptem

doneecho C4he sorted array isC Parr8X9M binary search on sorted arraylower^(uer^Kexr Pn + %Kwhile 8 Plower +le Puer 9do

sum^Kexr Plower ] PuerKmid^Kexr Psum / Kif 8 Parr8mid9M ^^ Psearch 9then

echo C4he element exists at indexC Pmidexit

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elif 8 Parr8mid9M +gt Psearch 9then

uer^Kexr Pmid + %Kelse

lower^Kexr Pmid ] %K

#doneecho C4he element was !A4 foundC

Output:

nter the number of inuts: >nter inut: ==nter inut: nter inut: ;;

nter inut: %%nter inut: nter the number to search:

4he sorted array is %% ;; ==4he element was !A4 found

nter the number of inuts: _nter inut: =;nter inut: 'nter inut: ;%

nter inut: 'nter inut: ;nter inut: _'nter inut: ;nter inut: '>nter the number to search: '

4he sorted array is ; ; ;% =; ' '> ' _'4he element exists at index '

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ASSIGNMENT '.1!5hec* if a gi$en word is a

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ASSIGNMENT '.2! 5ount the number of $owels in a word

Cod:

Q/bin/bash

echo +n Cnter the word: Cread strlen^Kexr length PstrKcount^(for i^%H iN^lenH i]]do

c^Kexr Pstr cut +c PiKif 8 Pc ^ 3a3 +o Pc ^ 3e3 +o Pc ^ 3i3 +o Pc ^ 3o3 +o Pc ^ 3u3 9then

count^Kexr Pcount ] %K

#doneecho C4he number of $owels isC Pcount

Output:

nter the word: umbrella4he number of $owels is ;

nter the word: ale

4he number of $owels is

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ASSIGNMENT '.%!?ccet or TeDect a string based on its length

Cod!Q/bin/bash

echo +n Cnter the string: Cread strlen^Kecho CPstrC wc +mKlen^Kexr Plen + %Kecho C4he number of characters isC Plen

if 8 Plen +ge %( 9then

echo C?ccetedCelse

echo CTeDectedC#

Output:

nter the string: 1ello is there anybody in there4he number of characters is ;%?cceted

nter the string: ale deli$ery

4he number of characters is %=?cceted

nter the string: madam4he number of characters is >TeDected

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ASSIGNMENT (.1!

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ASSIGNMENT (.2! 5reate a child rocess of the current rocess

Code:include Nstdio.hOinclude Nunistd.hO

int main$oid

int idHid ^ for*HrintfCIB^6d

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ASSIGNMENT (.%!Bemonstrate an orhan rocess

Code:include Nstdio.hOinclude Nunistd.hO

int main$oid

int idHid ^ for*Hif id ^^ (

slee>HrintfCIB^6d

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ASSIGNMENT (.!Bemonstrate a zombie rocess

Code:include Nstdio.hOinclude Nunistd.hO

int main$oid

int idHid ^ for*Hif id O (

slee>HrintfC

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Code:include Nstdio.hOinclude Nunistd.hOint main$oid

int idHid ^ for*Hif id ^^ (

rintfC51ILB

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include Nstdio.hOinclude Nunistd.hOint main

int id, iH

id ^ for*Hfor i^(H iN%(H i]]

if id O (

id ^ for*Hif id ^^ (

rintfCI am rocess 6d with

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ASSIGNMENT ).2!5reate ultile 5hild