FOSS Lab --V Prasad,2013

7/21/2019 FOSS Lab --V Prasad,2013

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FREE OPEN SOURCE SOFTWARE(FOSS) Lab

Manual.

R13 Syllabus JNTUK

Faculy

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Ass'ca" P!'"ss'! & *"# ' CSE.

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Raghu Institute of Technology II Year

II Sem Computers


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2

LA OJECT-%E

This is the BASIC Language at engineering level which gives a foundation for

the upcoming period.

Logical thinking is given for solving the given problem.

The learned c language can help a student at industry level.

ives enough knowledge in C basics.

!ore idea on Algorithms " #lowcharts.

$sage of Algorithms " #lowcharts.

%ifference between process and program can understood.

%ifference between Algorithm and &seudocode .

Several programs in C for perfection in syntactic " semantic representation.

'orking ability can be increases on (I )ditor and )!ACS editor in #)%*+A ,

S$S) linu-. (arious header file usages and the methodologies used for compiling them is

known umber Systems like BC% / *ctal / 0e-adecimal can be viewed.

Clear deviations in !achine Language / Assembly Language / Application

languages is done. Interesting topics like Arrays / &ointers / #unctions/ Structures " $nions can be

implemented. %iscussion a variety of current issues related to using C in educational settings.

%iscussion on advantages and disadvantages in C .

$sed Inbuilt (I )ditor from #)%*+A, S$SI Linu- and e-ecuted all programson it.

Came to know how secure the LI$1 operating system is.

Came to know the difference between programs and files.

2nown the difference between compile time e-ecution and run time e-ecution.

Completion of my lab taught me saying that C is an *cean and there is lot more

to work on.3 like graphics / multimedia / dynamic data collection 45

RA"a! ? P!'+!a22" 4 -- >"a!& 8:13019


II Sem Computers


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3

!anc, @ S"2"s"! 4 CSE @ -- S"2"s"!

E;#"!2"n1

S"ss'n01

a5Log into the systemOu#u 4 Login

b5$se vi editor to create a file called myfile.t-t which contains some te-t.Ou#u 4 vi mytable

c5correct typing errors during creation.Ou#u 4 &ractice vi editor commands6

d5Save the fileOu#u 4 7w8 9)nter

e5logout of the systemOu#u 4 logout

To Enter VI Editor:

T' Sa!

To use vi on a file/ type in vi filename. If the file named filename e-ists/ then thefirst page 3or screen5 of the file will be displayed: if the file does not e-ist/ then

an empty file and screen are created into which you may enter te-t.

vi filename edit filename starting at line 1

vi ;r filename recover filename that was being edited when systemcrashed

T' E;

$sually the new or modified file is saved when you leave vi. 0owever/ it is alsopossible to 8uit vi without saving the file.

N'"4 The cursor moves to bottom of screen whenever a colon 375 is typed. This type of command is completed by hitting the


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4

7- quit vi, writing out modified file to file named in original invocation

7w8 quit vi, writing out modified file to file named in original invocation

78 quit (or exit) vi

78> quit vi even though latest changes have not been saved for this vi call

S"ss'n08

a5Log into the system

b5open the file created in session ?c5Add some te-t

d5Change some te-te5%elete some te-tf5Save the ChangesOu#u 4 &ractice the commands in (i editor g5Logout of the system

N'" Ma" Us" ' 'll'/n+ c'22an$s

-ns"!n+ '! A$$n+ T";

The following commands allow you to insert and add te-t. )ach of these commandsputs the vi editor into insert mode: thus/ the


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5

cc change (replace) the entire current line, stopping when is hit

change (replace) the next lines, starting with the currentline, NccorcNcstopping when is hit

*"l"n+ T";

The following commands allow you to delete te-t.

B ;

N;

$/

$N/

delete single character under cursor

delete characters, starting with character under cursor delete the

single word beginning with character under cursor

delete words beginning with character under cursor! e"g", d#wdeletes # words

* delete the remainder of the line, starting with current cursor position

B$$ delete entire current line

N$$ or$N$ delete lines, beginning with the current line!

e"g", #dd deletes # lines


II Sem Computers


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E;#"!2"n8

a5Log into the system

b5$se the cat command to create a file containing the following data. Call it mytableuse tabs to separate the fields.

? +avi ?.DEF +amu D.GDHEF Sita ED.??F +au ?.HD

Ou#u

cat = mytable? +avi ?.DEF +amu D.GDHEF Sita ED.?

?F +au ?.HD

c5$se the cat command to display the file/mytable.Ou#u 4 Jcat mytable

?BC +avi ?.DEBF +amu D.GDHEF Sita ED.??CF +au ?.HD

d) $se the vi command to correct any errors in the file mytable./Ou#u 4 (erify the file with (i editor Commands

e) $se the sort command to sort the file mytable according to the first field. Callthe sorted file my table3 same name5Ou#u 4 Jsort 9? mytable = mytable

f) &rint the file mytableOu#u 4 cat mytable? +avi ?.D?F +au ?.HDEF +amu D.G

DHEF Sita ED.?

g5 $se the cut and paste commands to swap fields and E of mytable. Call it mytable 3same name5

Ou#u 4 Jcut Kf? =mytab? J cut ;f =mytab Jcut ;f E =my tabE


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Jpaste mytabE mytab =mytab Jpaste mytab?mytab = mytable

h5&rint the new file/ mytableOu#u 4 J cat mytable?BC ?.D +avi?CF ?.HD +auEBF D.G +amuDHEF ED.? Sita

i5Logout of the system.

Ca40000

ca to display a text file or to concatenate files

ca l"1displays contents of file? on the screen 3or window5without any screen breaks.

ca l"1 l"8

displays contents of file? followed by file on the

screen 3or window5 without any screen breaks.

ca )(l"1 )(l"8 C )(l"3 creates fileE containing file? followed by file

S'! 40000

The sort command sorts information piped into it. There are several options that

let you sort information in a variety of ways.#s 0" D s'!

T," 2's 2#'!an '#'ns n S'! 4

The following list describes the options and their arguments that may be used tocontrol how s'!functions.

#orcess'! to read from the standard input.$seful for reading frompipes andfiles simultaneously"

0c (erifies that the input is sorted according to the other optionsspecified on thecommand line. If the input is sorted correctly then

no output is provided. If the input is not sorted then s'! informsyou of the situation. The message resembles this. sort7 disorder7 This line not in sorted order. Km !erges the sorted input. s'! assumes the input is already

sorted. s'!normally merges input as it sorts. This option informss'!that the input is already sorted/ thus s'!runs much faster.

0' output Sends the output to file output instead of the standardoutput. Theoutputfile may be the same name as one of the inputfiles.

0u Suppress all but one occurrence of matching keys. ormally/ the


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entire line is the key. If field or character keys are specified/ thenthe suppressing is done based on the keys.

0y kmem$se%memkilobytes of main memory to initially start thesorting. If more memory is needed/ s'! automatically re8uests itfrom the operating system.

0 recs&Specifies the record siMe used to store each line. ormally the

recs&is setto the longest line read during the sort phase. If the Kc orKm options are specified/ the sort phase is not performed and thus therecord siMe defaults to a system siMe.

The amount of memory allocated for the sort impacts the speed of the sortsignificantly. If no kmem is specified, sort starts with the default amount ofmemory (usually 32K) The ma-imum 3usually ? !egabyte5 amount of memorymay be allocated if needed.

If F is specified for %mem/ the minimum 3usually ?D25 amount of memory isallocated.


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If this default siMe is not large enough/ s'!may abort during the merge phase. Toalleviate this problem you can specify a recs&that will allow the merge phase to runwithout aborting. E;#"!2"n3

S"ss'n14

a5Login to the system

b5$se the appropriate command to determine your login shell

Ou#u 4 Jecho JS0)LLsh

c5$se the ,etc,passwd file to verify the result of step b.

Ou#u 4 Jcat ,etc,passwd

d5$se the who command and redirect the result to a file called myfile?. $se themore command to see the contents of myfile?.

Ou#u 4 Jwho = myfile? N more

$ser? pts,F Apr E ?F7E

$ser pts,? !ay D ?H7?O

e5$se the date and who commands in se8uence 3in one line5 such that the outputof date will display on the screen and the output of who will be redirected to afile called myfile. $se the more command to check the contents of myfile.

Ou#u 4 J date : who = myfile

#ri April O ?D7G7E IST F?E Cat myfile 7

$serE pts, Apr ?F7E

$ser pts,E !ay H ?H7?OW,' 4000

The who command lets you display the users that are currently logged intoyour $ni- computer system.

/,'

This is the basic who command with no commandKline arguments. It shows the names ofusers that are currently logged in/ and may also show the terminal theyPre logged in on/and the time they logged in.


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/,' D 2'!"

In this e-ample the output of the who command is piped into the more command. Thisis useful when there are a lot of users logged into your computer system/ and part of theoutput of the who command scrolls off the screen. See the more command for moree-amples.

/,' 0a

The Ka argument lists all available output of the who command for each user.

&iping7KKK

To connect the output of the one command directly to the input of the other command.

This is e-actly what pipes do. The symbol for a pipe is the vertical bar N

#or e-ample/ typing

/,' D s'!

will give the same result as above/ but 8uicker and cleaner.

To find out how many users are logged on/ type
http://www.devdaily.com/unix/edu/examples/more.shtmlhttp://www.devdaily.com/unix/edu/examples/more.shtml


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/,' D /c 0lSession 7

-n#u Fl" 4 l"1.$a 4

Un; s Mulus"! OS

Un; /as $""l'#"$ by !an K"!n+,an an$ K"nT,'2s'n

a5'rite a sed command that deletes the first character in each line in a file.

Ou#u4s"$Ps,Q., ,file?.datn; s Mulus"! OS

n; /as $""l'#"$ by !an K"!n+,an an$ K"nT,'2s'n

b5'rite a sed command that deletes the last character in each line in a file.

Ou#u4

sed PJs,.J,,P file?.datUn; s Mulus"! O

Un; /as $""l'#"$ by !an K"!n+,an an$ K"nT,'2s'

c5'rite a sed command that swaps the first and second words in each line in afile.

Ou#u4sed Ke Ps,63RQ 6965 @63RQ 6965,6 6?,P

sed Ps,63RaKM@65 63RaKM@65,6 6?,P 3!odified " working5

3Substrings enclosed with 63 and 65 can be referenced with 6n 3n is a digit from ?to O5 5

+ef 7 http7,,www.grymoire.com,$ni-,Sed.htmluhKF
http://www.grymoire.com/Unix/Sed.html#uh-0http://www.grymoire.com/Unix/Sed.html#uh-0


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E;#"!2"n9

a5&ipe your ,etc,passwd file to awk/ and print out the home directory of each user.

Ou#u4cat ,etc,passwd N awk U V print JGW

b5%evelop an interactive grep script that asks for a word and a file name and then tellshow many lines contain that word.

Ou#u4

echo X)nter a wordYread word

echo X)nter the filenameYread filenolZgrep Kc Jword Jfile

echo X Jnol times Jword present in the JfileY

c5&art using awk

Ou#u4

echo X)nter a wordYread word

echo X)nter the filenameYread filenolZawk U,Jword, V print + W Infileecho X Jnol times Jword present in the JfileY

specifiedwords or patterns. #irst clear the screen/ then type

+!"# sc"nc" sc"nc".;

As you can see/ +!"#has printed out each line containg the word sc"nc".*r has it [[[[Try typing +!"# Sc"nc" sc"nc".;

The +!"#command is case sensitive: it distinguishes between Science and science.

To ignore upper,lower case distinctions/ use the Ki option/ i.e. type


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+!"# 0 sc"nc" sc"nc".;

To search for a phrase or pattern/ you must enclose it in single 8uotes 3the

apostrophe symbol5. #or e-ample to search for spinning top/ type

+!"# 0 Gs#nnn+ '#G sc"nc".;

Some of the other options of grep are7

0 display those lines that do *T match

0nprecede each matching line with the line

number0cprint only the total count of matched

lines

Try some of them and see the different results. %onPt forget/ you can use more than

one option at a time. #or e-ample/ the number of lines without the words scienceor Science is

+!"# 0c sc"nc" sc"nc".;

+ef 7 http7,,www.grymoire.com,$ni-,Awk.html
http://www.grymoire.com/Unix/Awk.htmlhttp://www.grymoire.com/Unix/Awk.html


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E;#"!2"nH

a5'rite a shell script that takes a command ;line argument and reports on whether it isdirectory/ a file/ or something else.

Ou#u4echo enterfile read strif test Kf Jstr

then echo file e-ists n it is an ordinaryfile elif test Kd Jstr

then echo directoryfile else

echo note-ists fiif test Kc Jstr

then echo character device

files fi

b5'rite a shell script that accepts one or more file name as arguments and converts all ofthem to uppercase/ provided they e-ist in the current directory.

Ou#u4

' get filename

echo Kn )nter #ile ame 7 read fileame

# ma%e sure file exits for reading

if R > Kf Jfileame then

echo #ilename Jfileame does note-ists e-it ?fi

# convert uppercase to lowercase using trcommand tr PRAK\P PRaKMP < Jfileame

c5'rite a shell script that determines the period for which a specified user is working onthe system.

Ou#u4

echo Xenter the login of theuserY read name

logindetailsZ]whoNgrep ;w XJnameY N grepXttyY if R J[ ;ne F then

echo XJname has not logged in


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yetY e-itfiloginhoursZ]echo XJlogindetailsY N cut ;c D/G]loginminutsZ]echo XJlogindetailsY N cut ;c OKEF]hoursnowZdate N cut ;c ?/?E]

minnow Z]date N cut ;c ?/?D]hourZ]e-pr Jloginhours K Jhoursnow]minZ]e-pr Jloginminuts K Jminnow]echo X Jname is working sinceJhour 0rs K Jmin !inutsY


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E;#"!2"nI

a5'rite a shell script that accepts a file name starting and ending line numbers asarguments and displays all the lines between the given line numbers.

Ou#u4

If R J Kne E then

echo Xchech the arguments onceYlastlineZwc ;l < J?

if R J ;lt Jlastline ;a JE Kle Jlastline thennlineZe-pr JE KJ 9 ?

echo Xtail 9J J? N head KJnlineY else

echo Xinvalid range specificationYfifi

b5 'rite a shell script that deletes all lines containing a specified word in one or morefiles supplied as arguments to it.

Ou#u4if R J Klt ?then

echo X Chech the arguments onceYe-itfi

echo X)nter awordY read word

for file inJ@ do

grep ;iv XJwordY Jfile N tee ?= ,dev,nulldoneecho X lines containing given word are deletedY


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E;#"!2"n

a5'rite a shell script that computes the gross salary of a employee according to thefollowing rules7

i5If basic salary is < ?FF then 0+A Z?F^ of the basic and %A ZOF^ of the basic.ii5If basic salary is =Z?FF then 0+A Z+sFF and %AZOH^ of the basic

The basic salary is entered interactively through the key board.

Ou#u4

echo enter basic salaryread salaZF.?

bZF.Hecho Jaecho hra is

hraZ]echo F.? 6@ JsalNbc] echo da is

daZ]echo F.H6@JsalNbc]gsalZe-pr Jhra 9 Jda 9Jsalecho Jgsal

b5'rite a shell script that accepts two integers as its arguments and computers the valueof first number raised to the power of the second number.

Ou#u4

If R J Kne then

echo Xchech the number of argumentsYcountZ?resultZ?

if R J ;ge F then

while R Jcount ;le J do

resultZ]e-pr Jresult 6@ J?]countZ]e-pr Jcount 9 ?]done

fi


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fiE;#"!2"n7

a5'rite an interactive fileKhandling shell program. Let it offer the user the choice ofcopying/ removing/ renaming/ or linking files. *nce the user has made a choice/ have theprogram ask the user for the necessary information/ such as the file name/ new name andso on.

b5'rite shell script that takes a login name as command ; line argument and reportswhen that person logs in

Ou#u4

Shell script that takes loginname as command line arg and reports when that person logsin.

if R J Klt ? thenecho improper usage

echo correct usage is7 JF usernamee-it

filognameZJ? while truedo

whoNgrep Jlogname=,dev,nullif R J[ Z F then

echo Jlogname has logged inecho Jlogname==shF?log.t-tdate ==shF?log.t-techo 0i = mesg.t-t

echo Jlogname == mesg.t-techo 0ave a ood %ay ==mesg.t-t mail Jlogname < mesg.t-t

e-itelsesleep DF fi done

c5'rite a shell script which receives two file names as arguments. It should checkwhether the two file contents are same or not. If they are same then second file shouldbe deleted.

S'l4

echo Xenter first file nameYread file?echo X enter second file nameYread filecmp file? file = fileE

if R KM Jfile? rm file


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fiecho Xduplicate file deleted successfullyY


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E;#"!2"n6

a5'rite a shell script that displays a list of all the files in the current directory to whichthe user has read/ write and e-ecute permissions.

Ou#u4

ls ;l N grep XQ.rw-Y N cut ;f O

b5%evelop an interactive script that ask for a word and a file name and then tells howmany times that word occurred in the file.

c5'rite a shell script to perform the following string operations7i5To e-tract a subKstring from a given string.ii5To find the length of a given string.

ote7 !ake use of #ollowing Link to know about Shell &rogramming

+ef 7 http7,,www.freeos.com,guides,lsst,chF.html
http://www.freeos.com/guides/lsst/ch02.htmlhttp://www.freeos.com/guides/lsst/ch02.html


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E;#"!2"n1:

'rite a C program that takes one or more file or directory names as command line input andreports the following information on the file7i5#ile typeii5umber of links

iii5+ead/ write and e-ecute permissionsiv5Time of last access

Ou#u4

include


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int stat3const char @restrictpath/ struct stat @restrict buf5:

*ESCR-PT-ON

Thestat35 function shall obtain information about the named file and write it to the areapointed to by the bufargument. Thepathargument points to a pathname naming a file. +ead/write/ or e-ecute permission of the named file is not re8uired. An implementation thatprovides additional or alternate file access control mechanisms may/ under implementationKdefined conditions/ causestat35 to fail. In particular/ the system may deny the e-istence of thefile specified bypath.

If the named file is a symbolic link/ the stat35 function shall continue pathnameresolution using the contents of the symbolic link/ and shall return information pertainingto the resulting file if the file e-ists.

The bufargument is a pointer to a sastructure/ as defined in the 7KKK

The sastructure shall contain at least the following members7

dev_t st_dev %evice I% of device containing file.ino_t st_ino #ile serial number.mode_t st_mode !ode of file 3see below5.

nlink_t st_nlink umber of hard links to the file.uid_t st_uid $ser I% of file.gid_t st_gid roup I% of file.dev_t st_rdev %evice I% 3if file is character or block special5.off_t st_siMe #or regular files/ the file siMe in bytes.

#or symbolic links/ the length in bytes of the pathname contained in the symbolic link.
http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.htmlhttp://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap04.html#tag_04_07http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.htmlhttp://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.htmlhttp://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap04.html#tag_04_07http://www.opengroup.org/onlinepubs/000095399/basedefs/sys/stat.h.html


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#or a shared memory obect/ the length in bytes.

#or a typed memory obect/ the length in bytes.

#or other file types/ the use of this field is unspecified.time_t st_atime Time of last access.time_t st_mtime Time of last data modification.time_t st_ctime Time of last status change.blksiMe_t st_blksiMe A file systemKspecific preferred I,* block

siMe for this obect. In some file system types/ this may vary fromfile to file.

umber of blocks allocated for this obect.


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E;#"!2"n11

'rite C programs that simulate the following uni- commands7a5mvOu#u4

include


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W

Sys"2 calls '! Fl" P!'c"ssn+ 7KKKK

#reeBS% 3.5 has si- fileKrelated system calls. The following table briefly describe thefunction of each.

Sys"2 calls Func'n

open open an e-isting file or create a new file

read +ead data from a file

write 'rite data to a file

lsee% !ove the read,write pointer to the specified location

close Close an open file

unlin% %elete a file

chmod Change the file protection attributes

stat +ead file information from inodes

#iles to be included for fileKrelated system calls.

'include

'include

'include


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Fla+ *"sc!#'n

+-+./ open for reading only

+0+./ open for writing only

+-0 open for reading and writing++.+23 do not block on open

+455E- append on each write

+2E46 create file if it does not e-ist

+6$2 truncate siMe to F

+E72. error if create and file e-ists

+89.+23 atomically obtain a shared lock

+E7.+23 atomically obtain an e-clusive lock

+-:E26 eliminate or reduce cache effects

+;8/2 synchronous writes

++;+..+0 do not follow symlinks

The flag 3+2E465 may be used to create the file if it does not e-ist. 'hen this flag isused/ the third parameter 3modes5 must be used to specify the file access permissionsfor the new file. Commonly used modes 3or access permissions5 include

C'nsan Na2"

Ocal

%alu"

S_I+'1$ FFFFGFF

S_I+$S+ FFFFFF

S_I'$S+ FFFFBFFS_I1$S+ FFFF?FF

S_I+'1* FFFFFFG

S_I+*T0 FFFFFFS_I'*T0 FFFFFFBS_I1*T0 FFFFFF?

read, 0 write, and 7executable

*"sc!#'n

,@ +'1 mask for owner @,

,@ + for owner @, ,@ 'for owner @, ,@ 1 forowner @,

,@ +'1 mask for other @,

,@ + for other @, ,@ 'for other @, ,@ 1 forother @,


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#or e-ample/ to open file tmp.t-t in the current working directory for readingand writing7

fd = open(tmp"txt, +-0)!

To open sample.t-t in the current working directory for appending or create it/ if itdoes not e-ist/ with read/ write and e-ecute permissions for owner only7

fd = open(tmp"txt, +0+./?+455E-?+2E46, 8:07$)!

A file may be opened or created outside the current working directory. In this case/ anabsolute path and relative path may prefi- the file name. #or e-ample/ to create a filein ,tmp directory7

open(tmptmp"txt, +-0)!

R"a$ !'2 l"s

The system call for reading from a file is read. Its synta- is

ssi&et read(int fd, void *buf, si&et nbytes)!

The first parameter fd is the file descriptor of the file you want to read from/ it isnormally returned from open. The second parameter buf is a pointer pointing thememory location where the input data should be stored. The last parameter nbytesspecifies the ma-imum number of bytes you want to read. The system call returns thenumber of bytes it actually read/ and normally this number is either smaller or e8ual to

nbytes. The following segment of code reads up to ?F bytes from file tmp.t-t7

int actual_count Z F:

int fd Z open3tmp.t-t/ *_+%*L`5:void @buf Z 3char@5 malloc3?F5:

actual_count Z read3fd/ buf/ ?F5:

)ach file has a pointer/ normally called read,write offset/ indicating where ne-t readwillstart from. This pointer is incremented by the number of bytes actually read by the readcall. #or the above e-ample/ if the offset was Mero before the readand it actually read?F bytes/ the offset will be ?F when the readreturns. This offset may be changed bythe system call lsee%/ which will be covered shortly.

W!" ' l"s

The system call writeis to write data to a file. Its synta- is

ssi&et write(int fd, const void *buf, si&et nbytes)!


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It writes nbytesof data to the file referenced by file descriptorfdfrom the buffer pointedby buf. The writestarts at the position pointed by the offset of the file. $pon returningfrom write/ the offset is advanced by the number of bytes which were successfullywritten. The function returns the number of bytes that were actually written/ or it returnsthe value K? if failed.


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E;#"!2"n18

'rite a C program that simulates ls Command

Ou#u4

include


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+ef 7 http7,,www.opengroup.org,onlinepubs,FFODOEOO,functions,opendir.html

!"a$$!()4000

NAME

readdir/ readdir_r K read a directory

S>NOPS-S

include


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The readdir35 function may buffer several directory entries per actual read operation:readdir35 shall mark for update the statime field of the directory each time thedirectory is actually read.

After a call to for%35/ either the parent or child 3but not both5 may continueprocessing the directory stream using readdir35/ rewinddir35/or see%dir35.If both theparent and child processes use these functions/ the result is undefined.

If the entry names a symbolic link/ the value of the dinomember is unspecified.

The readdir35 function need not be reentrant. A function that is not re8uired to bereentrant is not re8uired to be threadKsafe.

The readdirr35 function shall initialiMe the $!"nstructure referenced by entry torepresent the directory entry at the current position in the directory stream referred toby dirp/ store a pointer to this structure at the location referenced by result/ andposition the directory stream at the ne-t entry.

The storage pointed to by entryshall be large enough for a $!"nwith an array ofc,a! dnamemembers containing at least VA!)_!A1W9? elements.

$pon successful return/ the pointer returned at @resultshall have the same value as theargument entry. $pon reaching the end of the directory stream/ this pointer shall havethe value $LL.

The readdirr35 function shall not return directory entries containing empty names.

If a file is removed from or added to the directory after the most recent call toopendir35or rewinddir35/whether a subse8uent call toreaddirr35 returns an entryfor that file is unspecified.

The readdirr35 function may buffer several directory entries per actual readoperation: the readdirr35 function shall mark for update thestatimefield of thedirectory each time the directory is actually read.

Applications wishing to check for error situations should set errnoto F before callingreaddir35. Iferrno is set to nonKMero on return/ an error occurred.

RETURN %ALUE

$pon successful completion/ readdir35 shall return a pointer to an obect of type s!uc$!"n. 'hen an error is encountered/ a null pointer shall be returned and errno shallbe set to indicate the error. 'hen the end of the directory is encountered/a null pointershall be returned and errnois not changed.

If successful/ the readdirr35 function shall return Mero: otherwise/ an error numbershall be returned to indicate the error.
http://www.opengroup.org/onlinepubs/009695399/functions/fork.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/fork.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/rewinddir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/rewinddir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/seekdir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/seekdir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/opendir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/opendir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/rewinddir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/rewinddir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/fork.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/rewinddir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/seekdir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/opendir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/opendir.htmlhttp://www.opengroup.org/onlinepubs/009695399/functions/rewinddir.html


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33/51

?.W!" a n'n !"cu!s" s,"ll sc!# /,c, acc"#s any nu2b"! ' a!+u2"ns an$#!ns ,"2 n ," !""!s" '!$"! ('! ";a2#l"& ," sc!# s na2"$ !a+s& ,"n

";"cun+ !a+s AC s,'ul$ #!'$uc" CA 'n ," san$a!$ 'u#u

P!'+!a2 4

aZJecho umber of arguments are Ja-ZJ@cZJaresZPPwhile R ? Kle Jc docZ]e-pr Jc K ?]shift JcresZJresP PJ?set J-

doneecho Arguments in reverse order Jres

Ou#u

sh ?prg.sh a b co of arguments arguments are EArguments in reverse order c b a

. W!" a s,"ll sc!# ,a acc"#s /' l" na2"s as a!+u2"ns& c,"cs ,"#"!2ss'ns '! ,"s" l"s a!" $"ncal an$ ," #"!2ss'ns a!" $"ncal&

'u#u c'22'n #"!2ss'ns an$ ',"!/s" 'u#u "ac, l" na2" 'll'/"$ by s

#"!2ss'ns.

P!'+!a2 4

if R J Kne thenecho pass argumente-itfiecho enter file nameread f?echo enter the second file nameread fp?Z]ls Kl Jf? N cut Kc K?F]pZ]ls Kl Jf N cut Kc K?F]if R Jp? Z Jp thenecho permissions are sameecho Jp?


34/51

elseecho permissions are differentecho permission of file Jf? is Jp?echo permission of file Jf is Jpfi

Ou#u4

enter file name?Fa.shenter the second file namea.shpermissions are samerwKrKKrenter file name?enter the second file name

?Fa.shpermissions are differentpermission of file ? is rw-rw-rw-permission of file is rwKrKKr

E.W!" a s,"ll sc!# ,a a"s a al$ $!"c'!y na2" as an a!+u2"n an$!"cu!s"ly $"sc"n$ all ," sub$!"c'!"s& n$s ," 2a;2u2 alu" ' ,"

san$a!$ 'u#u.

P!'+!a24

clearif R J Kne ? thenecho ;e X6n6nInvalid umber of arguments passed6nYe-itficd J?echo The directory name is J?set KK ] ls Kl+N grep Kv Qd Nsort 9 K Krn]echo siMe of the largest file is J blocks

Ou#u

sh a.sh rvThe directory name is rvsiMe of the largest file is ?E? blocks

.A2 ' acc"#s a #a, na2" an$ c!"a"s all ," c'2#'n"ns n ,a #a,na2" as $!"c'!"s.

P!'+!a24


35/51

tempZI#SI#SZ,iZJfor i in J@

doif R Kf Ji thene-itfiif R Kd Ji thencd Jielsemkdir Jiecho Ji is in ]pwd]

cd JifidoneIfSZJtemp

Ou#u

sccselinu-7J sh b.sh d? d dEd? is in home scd is in home sc d?dE is in home sc d? d

.A2 ' s,'/ ," #!nn+ ' ,"! c'!!"s#'n$n+ ,'2" $!"c'!"s by acc"#n+al$ l'+0n na2"s as a!+u2"ns.

P!'+!a24

for nam in J@doyZ]grep Jnam ,etc,passwd N cut Kd 7 Kf?]if R Kn Jy thenif R Jy Z Jnam then-Z] grep Jnam ,etc,passwd N cut Kd 7 KfD]echo home directory of Jnam is J-elseecho Jnam doesnPt have an account fifidone


36/51

Ou#u 4

sh Ea.sh cse?F?home directory of cse?F? is ,home,cse?F?

sh Ea.sh csecse does not have an account

D.A2 ' 2#l"2"n "!2nal l'cn+ (s2la! ' ," l'c c'22an$). N' 2"l2 n""$ b" 2#l"2"n"$ '! ," l'c $u!a'n.

P!'+!a2

clearstty Kechoecho enter password to lock the terminal

read pass?echo +eKenter passwordread passif R Jpass? Z Jpass thenecho system is lockedecho enter password to unlocktrap ]],? E O ? ?Hwhile truedoread passEif R Jpass? Z JpassE then echo system unlockedstty echoe-itelseecho password mismatchfidoneelseecho password mismatchstty echofi

Ou#u4

enter the password to lock terminal 7@@@@reKenter the password7@@@@system is lockedenter the password to unlock7@@@@


37/51

system unlockedenter the password to lock terminal7@@@@@@@@reKenter the password7@@@@password mismatch

G.C!"a" a sc!# l" call"$ l" #!'#"!"s ,a !"a$s a l" na2" "n"!"$ an$'u#uss #!'#"!"s

P!'+!a24

echo enter a filenameread fileif R Kf Jfile thenset KK ]ls Kl Jfile]

echo file permission J?echo number of link Jecho user name JEecho owner name Jecho block siMe Jecho date of modification JDecho time of modification JGecho name of file JHelseecho file does not e-itfi

Ou#u

?5enter a filename ?Fa.shfile permission KrwKrKKrKKnumber of links ?user name scowner name scblock siMe DDdate of modification FFOKF?KOtime of modification F7EFname of file ?Fa.sh

5

enter a filenametestfile does not e-it


38/51

H.W!" a s,"ll sc!# ,a acc"# 'n" '! 2'!" l" na2"s as a!+u2"n an$ c'n"!all ' ,"2 ' u##"!cas"& #!'$"$ ,"y ";s n cu!!"n $!"c'!y.

P!'+!a24

clearif R J Ke8 F then Xecho enter the argumentsYe-itfifor i in J@doif R Kf Ji thenecho it is a valid file

echo Contents of file before convertingcat Jiecho Contents of file after convertingtr PRaKMP PRAK\P < JikZ]ls Ji N tr PRaKMP PRAK\P]mv Ji Jkecho file Ji renamed as J-lselseecho file does not e-istfidone

Ou#u

Jsh b.sh testIt is a valid filefile test renamed as T)ST?Fb.sh ?b.awk ?bprg.sh a.sh a.sh Da.sh Ha.sh a? d? first rv T)ST -Jsh b.sh program?file does not e-ist

O./!" a s,"ll sc!# ,a $s#lay all ," lns ' a l" s#"c"$ as ," !a!+u2"n ' ," sc!#. T," s"c'n$ a!+u2"n& /,c, /s '#'nal& can b" us"$ '

s#"cy n /,c, ," s"a!c, s ' b"+n n cu!!"n /'!n+ $!"c'!y& -n ","!

cas"& ," sa!n+ $!"c'!y as /"ll as all s sub$!"c'!"s a all l""ls 2us b"

s"a!c,"$. T," sc!# n""$ n' nclu$" any "!!'! c,"cn+

P!'+!a24


39/51

if R J Ke8 ? then pwd=tmcat tmelsetmZJ

echo Jtmfit?Z]ls Kali+ N grep J? N cut Kc ?KH ]ls Kalir Jtm N grep Jt? Ncut Kc DK = techo the links arecat t

Ou#u

sh a.sh firstlinks are

?EHEOG KrwKrKKrKK ? sc sc ?F FFOKF?KO F?7D firstsccselinu-7J ln first tempsccselinu-7J sh a.sh templinks are?EHEOG KrwKrKKrKK sc sc ?F FFOKF?KO F?7D first?EHEOG KrwKrKKrKK sc sc ?F FFOKF?KO F?7D temp

?F.W!" a s,"ll sc!# ,a acc"#s as l"na2" as a!+u2"n an$ $s#lay sc!"a'n 2" l" ";ss an$ $'"s n' s"n$ 'u#u "!!'! 2"ssa+"

P!'+!a24

if R J Ke8 F thenecho enter the argumentse-itfiif R ;f J? thentimeZ]ls ;l J? N cut ;c K]echo file J? was created on Jtimeelseecho file J? does not e-istfi

Ou#u 4

sh b.sh tempfile temp was created on FFOKF?KO F?7Dsh b.sh temp??


40/51

file temp?? does not e-ist

??.W!" a s,"ll sc!# ' $s#lay ," cal"n$a! '! cu!!"n 2'n, /, cu!!"n$a"!"#lac"$ by B '! BB $"#"n$n+ 'n /,","! ," $a" ,as 'n" $+ '! /' $+s.

P!'+!a24dZ]date 9^d]cal = cal?if R Jd Kle O thensed Ps,PJdP,@,P cal?e-itfised Ps,PJdP, @@,P cal?

Ou#u 4

anuary FFOSu !o Tu 'e Th #r Sa? E D G H O ?F?? ? ?E ? ? ?D ?G?H ?O F ? E D G H O EF @@

?.W!" a s,"ll sc!# ' n$ s2all"s ' 3 nu2b"!s ,a a!" !"a$ !'2 "yb'a!$.

P!'+!a24

echo enter first numberread aecho enter second numberread becho enter third numberread cif R Ja Ke8 Jb Ka Jb Ke8 Jc thenecho all numbers are e8uale-itfiif R Ja Klt Jb thens?ZJasZJbelse


41/51

s?ZJbsZJafiif R Js? Kgt Jc then

sZJs?s?ZJcfiecho smallest number is Js?

Ou#u 4

enter first number7enter second number7DGenter third number 7smallest number is

enter first number7Fenter second number7Fenter third number 7Fall numbers are e8ual

13. W!" a s,"ll sc!# usn+ ";#! c'22an$ ' !"a$ n a s!n+ an$ $s#lay a

suabl" 2"ssa+" $'"s n' ,a" al"as 1: c,a!ac"!s

P!'+!a24

clearecho enter the stringread slZ]e-pr length Js]if R Jl Kgt ?F thenecho string has more than ?F characterselseecho string has less than ?F charactersfi

Ou#u 4

enter the stringsaipaulstring has less than ?F charactersenter the stringengineeringstring has more than ?F characters


42/51

?.W!" a s,"ll sc!# ' c'2#u" ," su2 ' nu2b"! #ass"$ ' as a!+u2"n 'nc'22an$ ln" an$ $s#lay ," !"sul.

P!'+!a24

clearif R J Ke8 F thenecho no argumentse-itelsesumZFfor i in J@dosumZ]e-pr Jsum 9 Ji]done

echo sum of the numbers is Jsumfi

Ou#u

J sh Gb.sh ?F ?F Fsum of the numbers is FJ sh Gb.sh ?F ?FF FFsum of the numbers is E?F

?.A2 ' c'2#u" +!'ss sala!y ' an "2#l'y"" &acc'!$n+ly ' !ul" +"n b"l'/.- basc sala!y s 1H::: ,"n =RA 1: ' basc an$ *A 6: ' basc

- basc sala!y s 1H::: ,"n =RA H:: an$ *A 67 ' basc

P!'+!a24

clearecho enter the basicread basicif R Jbasic Klt ?FFF thenhraZ]echo scaleZ: Jbasic @ F.? N bc]daZ]echo scaleZ: Jbasic @ F.O N bc]elsehraZFFdaZ]echo scaleZ: Jbasic @ F.OH N bc]figsZ]echo scaleZ:Jbasic 9Jhra 9Jda N bc]echo gross Z Jgsecho hra Z Jhra


43/51

echo da Z Jda

Ou#u

J sh Ha.sh

enter the basic pay?FFFgross Z FFF.Fhra Z ?FF.Fda Z OFF.FJ sh Ha.shenter the basicFFFFgross Z F?FF.FFhra Z FFda Z ?ODFF.FF

1I. W!" a s,"ll sc!# ' $"l"" all ln"s c'nann+ a s#"cc /'!$ n 'n" '! 2'!"

l" su##l"$ as a!+u2"n ' .

P!'+!a24

clearif R J Ke8 F thenecho no arguments passede-itfiecho the contents before deletingfor i in J@doecho Jicat Jidoneecho enter the word to be deletedread wordfor i in J@dogrep Kvi Jword Ji = tempmv temp Jiecho after deletingcat Jidone

Ou#u4


44/51

J sh Hb.sh test?the contents before deletingtest?hello rvce

hello csebangaloremysore cityenter the word to be deletedcityafter deletinghello rvcehello csebangaloreJ sh Hb.shno argument passed

?D.W!" a s,"ll sc!# ,a +"s ";"cu"$ $s#lays ," 2"ssa+" ","!


45/51

strZ]cat J? N tr P6nP P P]for a in Jstrdoecho 'ord Z Ja/ Count Z ]grep Kc Ja J]done

Ou#u 4

J cat testhello rvce cseJ cat test?hello rvce csehello rvce csehelloJ sh ?.sh test test?'ord Z hello/ Count Z E

'ord Z rvce/ Count Z 'ord Z cse/ Count Z

?H.W!" a s,"ll sc!# ,a $""!2n"s ," #"!'$ '! /,c, s#"c"$ us"! s/'!n+ 'n ," sys"2.

P!'+!a24

echo X)nter the Login ame of a $serYread namecountZ]who N grep ;wo XJuserY N wc ;c]if R Jcount ;e8 F thenecho Xinvalid userYe-itfiif RJcount ;gt thenecho X!ultiple LoginYelseltZ]who N grep XuserY N cut ;c EKEH]lhZ]echo Jlt N cut ;c ?K]lmZ]echo Jlt N cut ;c K]chZ]date 9^0]cmZ]date 9^!]if R Jcm ;gr Jlm thensmZ]e-pr Jcm KJlm]shZ]e-pr Jch K Jlh]else


46/51

smZ]e-pr DF K Jlm KJcm]shZ]e-pr Jch K Jlh ; ?]fiecho X The user is logged in from Jsh hour Jsm minutesYfi

Ou#u 7

?5 )nter the user name 7cse?OThe user is logged in from ? hour F minutes5 )nter the user name7abcInvalid user

?O.W!" a s,"ll sc!# ,a !"#'!s ," l'++n+ n ' a s#"c"$ us"! /,n 'n"2nu" a"! ,"@s," l'+s n. T," sc!# au'2acally "!2na"s ," s#"c"$

us"! $'"s n' l'+n $u!n+ a s#"c"$ #"!'$ ' 2"

P!'+!a24

echo )nter the login name of the user7Yread userperiodZFwhile R truedovarZ]who N grep ;w XJuserY]lenZ]echo XJvar N wc ;c]if R Jlen ;gt ? thenecho XJuser logged in Jtm secondsYe-itelsesleep ?tmZ]e-pr Jtm 9 ?]fiif R Jtm ;e8 D? thenecho XJuser did not login within ? minuteYe-itfidone

Ou#u 4

)nter the login name of the user 7cse?Ocse?O logged in seconds)nter the login name of the user 7cseF


47/51

cseF did not login within ? minute

8:. W!" a s,"ll sc!# ,a acc"#s /' n"+"!s as s a!+u2"ns an$ c'2#u"s

," alu" ' !s nu2b"! !as"$ ' ," #'/"! ' ," s"c'n$ nu2b"!.

P!'+!a24

if R J Kne thenecho )rror 7 Invalid no. of arguments.e-itfipwrZ]echo J? Q J N bc]echo J? Q J Z Jpwr

Ou#u4

Jsh ??a.sh EQE Z H

81. W!" a s,"ll sc!# ,a acc"#s a l"na2"& sa!n+ an$ "n$n+ ln" nu2b"!s

as a!+u2"ns an$ $s#lays all ," ln"s b"/""n ," +"n ln" nu2b"!s.

P!'+!a24

if R J Kne E then echo )rror 7 Invalid number of arguments.e-itfiif R J Kgt JE thenecho )rror 7 Invalid range value.e-itfilZ]e-pr JE K J 9 ?]cat J? N tail 9J N head KJl

Ou#u4

Jsh ??b.sh test Gabc ?Edef DGHghi O?F??


48/51

.W!" a s,"ll sc!# ,a 'l$s l'n+ ln"s n' 9: c'lu2ns. T,us any ln" ,a";c""$s 9: c,a!ac"!s 2us b" b!'"n a"! 9:, aQ s ' b" a##"n$"$ as ,"

n$ca'n ' 'l$n+ an$ ," #!'c"ssn+ s ' b" c'nnu"$ /, ," !"s$u". T,"

n#u s ' b" ,!'u+, a "; l" c!"a"$ by ," us"!.

P!'+!a24

echo X )nter the filename 76cYread fnfor ln in ]cat Jfn]dolgthZ]echo Jln N wc Kc]lgthZ]e-pr Jlgth K ?]sZ?:eZif R Jlgth Kgt F then

while R Jlgth Kgt F doecho ]echo Jln N cut Kc JsKJe]66sZ]e-pr Je 9 ?]eZ]e-pr Je 9 F]lgthZ]e-pr Jlgth K F]doneecho Jln N cut Kc Jselseecho Jlnfidoneecho X#ile #olded Y

OUTPUT

Jsh ?a.sh)nter the filename 7 test#ile #olded

E.W!" a a/ sc!# ,a acc"#s $a" a!+u2"n n ," '!2 ' 220$$0yy an$$s#lays n ," '!2 any &2'n, &y"a!. T," sc!# s,'ul$ c,"c ," al$y '

," a!+u2"n an$ n ," cas" ' "!!'!& $s#lay a suabl" 2"ssa+".

B)IVsystem3XclearY5:daZYE?HE?EFE?EFE?E?EFE?EFE?YmoZYA#)B!A+A&+!A`$$LA$S)&*CT*(%)CYmmZsubstr3A+(R?/?/5ddZsubstr3A+(R?//5


49/51

yyZsubstr3A+(R?/G/5if3dd = substr3da/KmmK?/5 NN 3mm=?5 NN A+C >Z5print XInvalid dateYelseprint XThe day is ^d 6n The month is ^s 6n

The year is ^d 6nY/dd/substr3mo/E@mmK/E5yyW

Ou#u 4

Jawk Kf ?b.awk ?K?FKFFHThe day is ?FThe month is *CTThe year is FFH

.W!" an a/ sc!# ' $"l"" $u#lca"$ ln" !'2 a "; l". T," '!$"! ' ,"

'!+nal ln"s 2us !"2an unc,an+"$.

P!'+!a24

B)IVaRn99ZJFW)%Vfor3iZF:i


50/51

bangaloreJ awk 0f ?Ea.awk testcollegeBangalore

.W!" an a/ sc!# ' n$ 'u 'al nu2b"! ' b''s s'l$ n "ac, $sc#ln"as /"ll as 'al b'' s'l$ usn+ ass'ca" a!!ay $'/n abl" as +"n"l"c!cal 39

2"c,ancal I

"l"c!cal 7:

c'2#u"!s 93

2"c,ancal IH

cl 167

c'2#u"!s I9

P!'+!a24

B)I Vprint XT*TAL $!B)+ *# B**2S S*L% I )AC0 CAT)*+`YWV booksRJ?9ZJW)% Vfor 3item in books5Vprintf 3X ^s soldZ ^d6nY/item/booksRitemWtotal 9ZbooksRitemWprintf3YTotal books soldZ^dY/total5W

Ou#u 4

T*TAL $!B)+ *# B**2S S*L% I )AC0 CAT)*+`electrical ??mechanical ?EGcomputers ?FGcivil ?OHTotal books sold Z D

D.W!" an a/ sc!# ' c'2#u" +!'ss sala!y ' an "2#l'y"" acc'!$n+ly '!ul" +"n b"l'/ - basc sala!y 1:::: ,"n *A 9H ' the basc an$ =RA

1H ' basc - basc sala!y 1:::: ,"n *A H: ' the basc an$ =RA

8: ' basc

P!'+!a24

B)I V printf )nter the Basic &ay 7 +s. getline bp < ,dev,tty


51/51

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FOSS Lab --V Prasad,2013

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