If you're looking for the top 100 linux interview questions and answers, then you've come to the right place. We at hirist have compiled a list of the top linux interview questions that are asked by companies like TCS, Infosys, Wipro, HCL and Cognizant and put it together in a pdf format that can be downloaded for free.
You can easily download this free linux interview questions pdf file and use it to prepare for an interview. It doesn't matter if you're looking for linux interview questions and answers for freshers or linux interview questions and answers for experienced because this presentation will cater to both segments.
This list includes Linux interview questions and answers in the below categories:
top 100 linux interview questions
kickstart linux interview questions
interview questions on linux boot process
top 100 linux interview questions answers
linux interview questions 2009
linux installation interview questions
interview question on linux commands
linux interview topics
top 50 linux interview questions
Top 30 linux system admin interview questions & answers
Top 25 Unix interview questions with answers
Linux Interview Questions
Practical Interview Questions and Answers on Linux
Top 100 Informatica Interview Questions
10 Linux and UNIX Interview Questions and Answers
linux interview questions and answers for freshers
linux interview questions and answers pdf
linux interview questions and answers pdf free download
linux interview questions and answers for experienced pdf
linux l2 interview questions and answers
linux system administrator interview questions and answers
basic linux interview questions and answers
red hat linux interview questions and answers
2. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisLinuxandwhyisitsopopular?
2
QUESTION
LinuxisanoperatingsystembasedonUNIX,andwasfirstintroducedbyLinusTorvaldscommonlyusedinservers. ItisbasedontheLinuxKernel,andcanrunondifferenthardwareplatformsmanufacturedbyIntel,MIPS,HP, IBM,SPARCandMotorola.AnotherpopularelementinLinuxisitsmascot,apenguinfigurenamedTux.
PopularityofLinuxisbecauseofthefollowingreasons
•Itisfreeandopensource.WecandownloadLinuxforfreeandcustomizeitasperourneeds.
•Itisveryrobustandadaptable.
•Immenseamountoflibrariesandutilities
ANSWER
QUESTION 1
3. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisBASH?
3
QUESTION
BASHisshortforBourneAgainSHell.ItwaswrittenbySteveBourneasareplacementtotheoriginalBourneShell(representedby/bin/sh).ItcombinesallthefeaturesfromtheoriginalversionofBourneShell,plusadditionalfunctionstomakeiteasierandmoreconvenienttouse.IthassincebeenadaptedasthedefaultshellformostsystemsrunningLinux.
ANSWER
QUESTION 2
4. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthecoreofLinuxOperatingSystem?
4
QUESTION
ThecoreoftheLinuxoperatingsystemisKernel.ItisbrokendownintoShell,Command,Script,andTerminal.ShellisacommandLineInterpreter,CommandisuserInstructiontoComputer,Scriptiscollectionofcommandsstoredinafile,andTerminalisacommandLineInterface.
ANSWER
QUESTION 3
5. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthebasicdifferencebetweenUNIXandLinuxOperatingSystem?
5
QUESTION
Linuxisfreeandopen-sourcesoftware(allowingprogrammerstoprogramwithLinuxnotaroundit),thekernelofwhichiscreatedbyLinusTorvaldsandcommunity.UNIX,ontheotherhand,isUNIXiscopyrightednameonlybigcompaniesareallowedtousetheUNIXcopyrightandname,soIBMAIXandSunSolarisandHP-UXallareUNIXoperatingsystems.
ANSWER
QUESTION 4
6. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisLILO?
6
QUESTION
LILOisabootloaderforLinux.ItisusedmainlytoloadtheLinuxoperatingsystemintomainmemorysothatitcanbeginitsoperations.
ANSWER
QUESTION 5
7. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisanINODE?
7
QUESTION
Allfileshaveitsdescriptionstoredinastructurecalled„inode‟.Theinodecontainsinfoaboutthefile-size,accessandmodificationtime,permissionandsoon.Inadditiontodescriptionsaboutthefile,theinodecontainspointerstothedatablocksofthefile.
ANSWER
QUESTION 6
8. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisaswapspace?
8
QUESTION
AswapspaceisacertainamountofspaceusedbyLinuxtotemporarilyholdsomeprogramsthatarerunningconcurrently.ThishappenswhenRAMdoesnothaveenoughmemorytoholdallprogramsthatareexecuting.
ANSWER
QUESTION 7
9. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatistheadvantageofopensource?
9
QUESTION
Opensourceallowsyoutodistributeyoursoftware,includingsourcecodesfreelytoanyonewhoisinterested. Peoplewouldthenbeabletoaddfeaturesandevendebugandcorrecterrorsthatareinthesourcecode.Theycanevenmakeitrunbetter,andthenredistributetheseenhancedsourcecodefreelyagain.Thiseventuallybenefitseveryoneinthecommunity.
ANSWER
QUESTION 8
10. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthebasicdifferencebetweenBASHandDOS?
10
QUESTION
ThekeydifferencesbetweentheBASHandDOSconsoleliesin3areas:
-BASHcommandsarecasesensitivewhileDOScommandsarenot;
-underBASH,/characterisadirectoryseparatorandactsasanescapecharacter.UnderDOS,/servesasacommandargumentdelimiterandisthedirectoryseparator
-DOSfollowsaconventioninnamingfiles,whichis8characterfilenamefollowedbyadotand3characterfortheextension.BASHfollowsnosuchconvention.
ANSWER
QUESTION 9
11. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthedifferencebetweenTCPandUDP?
11
QUESTION
ThebasicdifferenceisthatTCPestablishesaconnectionbeforesendingdataandthisallowsittocontrolthedataflowandguaranteethatallpacketsgetdelivered.UDPsimplychucksdatagramsontothewireandifsomegetlostorarriveinbadorderthere‟snowaytorequestaresend.HoweverUDPhaslownetworkoverheadsosomeservicessuchasDNSresolution,SNMP,DHCP,RIPandVOIPuseUDPforitsspeedandanyerrorsareusuallydealtwithontheapplicationlayerratherthannetworklayer.
ANSWER
QUESTION 10
12. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatistheimportanceoftheGNUproject?
12
QUESTION
Thisso-calledFreesoftwaremovementallowsseveraladvantages,suchasthefreedomtorunprogramsforanypurposeandfreedomtostudyandmodifyaprogramtoyourneeds.Italsoallowsyoutoredistributecopiesofasoftwaretootherpeople,aswellasfreedomtoimprovesoftwareandhaveitreleasedtothepublic.
ANSWER
QUESTION 11
13. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowdoesDNSresolutionwork?
13
QUESTION
AclientapplicationrequestsanIPaddressfromthenameserverusuallybyconnectingtoUDPport53.ThenameserverwillattempttoresolvetheFQDNbasedonitsresolverlibrary,whichmaycontainauthoritativeinformationaboutthehostrequestedorcacheddataaboutthatnamefromanearlierquery.Ifthenameserverdoesnotalreadyhavetheanswer,itwillturntorootnameserverstodeterminetheauthoritativefortheFQDNinquestion. Then,withthatinformation,itwillquerytheauthoritativenameserversforthatnametodeterminetheIPaddress.
ANSWER
QUESTION 12
14. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Describetherootaccount.
14
QUESTION
Therootaccountislikeasystemsadministratoraccount,andallowsyoufullcontrolofthesystem.Hereyoucancreateandmaintainuseraccounts,assigningdifferentpermissionsforeachaccount.ItisthedefaultaccounteverytimeyouinstallLinux.
ANSWER
QUESTION 13
15. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisCLI?
15
QUESTION
CLIisshortforCommandLineInterface.Thisinterfaceallowsusertotypedeclarativecommandstoinstructthecomputertoperformoperations.CLIoffersanadvantageinthatthereisgreaterflexibility.However,otheruserswhoarealreadyaccustomwithusingGUIfinditdifficulttoremembercommandsincludingattributesthatcomewithit.
ANSWER
QUESTION 14
16. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisGUI?
16
QUESTION
GUI,orGraphicalUserInterface,makesuseofimagesandiconsthatusersclickandmanipulateasawayofcommunicatingwiththecomputer.Insteadofhavingtorememberandtypecommands,theuseofgraphicalelementsmakesiteasiertointeractwiththesystem,aswellasaddingmoreattractionthroughimages,iconsandcolors.
ANSWER
QUESTION 15
17. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowcanyoufindouthowmuchmemoryLinuxisusing?
17
QUESTION
Fromacommandshell,usethe“concatenate”command:cat/proc/meminfoformemoryusageinformation.Youshouldseealinestartingsomethinglike:Mem:64655360,etc.ThisisthetotalmemoryLinuxthinksithasavailabletouse.
ANSWER
QUESTION 16
18. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisanMXrecord?
18
QUESTION
AnMXrecordnumericallyranksthemailserversyouwouldprefertoreceiveemailforadomain.TheMXrecordwiththelowestnumberispreferredovertheothers,butyoucansetmultipleemailserverswiththesamevalueforsimpleloadbalancing.
ANSWER
QUESTION 17
19. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
PleasedescribetheLinuxboot-upsequence.
19
QUESTION
Therearesevenstepstotheboot-upsequence.1)BIOS(basicinput/outputsystem)–executestheMBRwhereBootLoadersits,2)MBR-MasterbootreadsKernelintomemory,3)GRUB(GrandUnifiedBootloader)KernelstartsInitprocess,4)Kernel–Kernelexecutesthe/sbin/initprogram.Initreadsinittab,executesrc.sysinit,5)Init–thercscriptthanstartsservicestoreachthedefaultrunleveland6)Runlevelprograms–theseprogramsareexecutedfrom/etc/rc.d/rc*.dl/
ANSWER
QUESTION 18
20. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatistypicalsizeforaswappartitionunderaLinuxsystem?
20
QUESTION
Thepreferredsizeforaswappartitionistwicetheamountofphysicalmemoryavailableonthesystem.Ifthisisnotpossible,thentheminimumsizeshouldbethesameastheamountofmemoryinstalled.
ANSWER
QUESTION 19
21. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Howdoyousearchforapatternandthenreplaceitinanentirefile?
21
QUESTION
YouuseSed,orinVieditor,thesearchusescharacter„s‟slashthepatterntobesearched,slashthepatterntoreplaceitwith,slash„g‟whichstandsforentirefile.
ANSWER
QUESTION 20
22. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
DoestheCtrl+Alt+DelkeycombinationworkonLinux?
22
QUESTION
Yes,itdoes.JustlikeWindows,youcanusethiskeycombinationtoperformasystemrestart.Onedifferenceisthatyouwon‟tbegettinganyconfirmationmessageandtherefore,rebootisimmediate.
ANSWER
QUESTION 21
23. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowdoyoulistandflushallIptables?
23
QUESTION
Firstyouusethe–Lswitchtoviewallthecurrentlypresentrulesandthen–Ftoflushthem.
ANSWER
QUESTION 22
24. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowdoyouchangepermissionsunderLinux?
24
QUESTION
Assumingyouarethesystemadministratorortheownerofafileordirectory,youcangrantpermissionusingthechmodcommand.Use+symboltoaddpermissionor–symboltodenypermission,alongwithanyofthefollowingletters:u(user),g(group),o(others),a(all),r(read),w(write)andx(execute).Forexamplethecommandchmodgo+rwFILE1.TXTgrantsreadandwriteaccesstothefileFILE1.TXT,whichisassignedtogroupsandothers.
ANSWER
QUESTION 23
25. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisashell?Whataretheirnames?
25
QUESTION
Theshellisthepartofthesystemwithwhichtheuserinteracts.AUnixshellinterpretscommandssuchas“pwd”, “cd”or“traceroute”andsendstheproperinstructionstotheactualoperatingsystemitself.TheshellscurrentlyavailableareAnsSH,BASH,CSH,TCSH,NOLOGIN,KSH.Otherfunctionsofashellincludescriptingcapability, pathmemory,multitasking,andfilehandling.
ANSWER
QUESTION 24
26. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
InLinux,whatnamesareassignedtothedifferentserialports?
26
QUESTION
Serialportsareidentifiedas/dev/ttyS0to/dev/ttyS7.ThesearetheequivalentnamesofCOM1toCOM8inWindows.
ANSWER
QUESTION 25
27. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisazombie?
27
QUESTION
Cheekyanswersgetbonuspointsforthisone.ButintheLinuxworld,azombieprocessistheprocessoutputof„ps‟ bythepresenceof„Z‟intheSTATcolumn.Zombiesareessentiallytheprematureprocesseswhosematureparentprocessesdiedwithoutreapingitschildren.Notethatzombiescan‟tbekilledwiththeusual„kill‟signal.
ANSWER
QUESTION 26
28. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowdoyouaccesspartitionsunderLinux?
28
QUESTION
Linuxassignsnumbersattheendofthedriveidentifier.Forexample,ifthefirstIDEharddrivehadthreeprimarypartitions,theywouldbenamed/numbered,/dev/hda1,/dev/hda2and/dev/hda3.
ANSWER
QUESTION 27
29. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Youneedtodefineamacro,akeybindingfortheexistingcommand.Howwouldyoudoit?
29
QUESTION
Thereisacommandcalledbind,inbashshellwhichiscapableofdefiningmacro,orbindingakey.Inordertobindakeywithanexistingcommand,weneedtogenerateCharacterSequenceemittedbythekey.PressCtrl+vandthenkeyF12,Igot^[[24~
ANSWER
QUESTION 28
30. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Yourassistantneedstoprintdirectorystack,whatwouldyousuggest?
30
QUESTION
TheLinuxcommand'dirs',willprintthedirectorystack.
ForExample:[root@localhost~]#dirs
/usr/share/X11
ANSWER
QUESTION 29
31. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthemaximumlengthforafilenameunderLinux?
31
QUESTION
Anyfilenamecanhaveamaximumof255characters.Thislimitdoesnotincludethepathname,sothereforetheentirepathnameandfilenamecouldwellexceed255characters.
ANSWER
QUESTION 30
32. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatdoesthecommand'hash'isusedforinbashShell?
32
QUESTION
Linuxcommand'hash'managesinternalhashtable,finsandrememberfullpathofthespecifiedcommand,Displayusedcommandnamesandnumberoftimesthecommandisused.
[root@localhost~]#hash
hitscommand
2/bin/ls
2/bin/su
ANSWER
QUESTION 31
33. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whichbuilt¬inLinuxcommandperformsarithmeticoperationofIntegersinBash?
33
QUESTION
The'let'commandthatperforms,arithmeticoperationofintegerinbashshell.
#!/bin/bash
...
...
letc=a+b
…
...
ANSWER
QUESTION 32
34. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Explainvirtualdesktop.
34
QUESTION
Thisservesasanalternativetominimizingandmaximizingdifferentwindowsonthecurrentdesktop.Usingvirtualdesktops,eachdesktopisacleanslatewhereyoucanopenoneormoreprograms.Ratherthanminimizing/restoringallthoseprogramsasneeded,youcansimplyshufflebetweenvirtualdesktopswithprogramsintactineachone.
ANSWER
QUESTION 33
35. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Differentiatemultiuserfrommultitask.
35
QUESTION
Multiusermeansthatmorethanonepersoncanusethecomputeratthesametime.Multitaskmeansthatevenasingleusercanhavethecomputerworkonmorethanonetaskorprogramatthesametime.
ANSWER
QUESTION 34
36. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Youhavealargetextfile,andyouneedtoseeonepageatatime.Whatwillyoudo?
36
QUESTION
Youcanachievetheaboveresultbypipelingtheoutputof'catfile_name.txt'with'more'command.
[root@localhost~]#catfile_name.txt|more
ANSWER
QUESTION 35
37. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whoownthedatadictionary?
37
QUESTION
Theuser'SYS'ownsthedatadictionary.Users'SYS'and'SYSEMarecreatedbydefault,automatically.
ANSWER
QUESTION 36
38. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowdoyoushareaprogramacrossdifferentvirtualdesktopsunderLinux?
38
QUESTION
Toshareaprogramacrossdifferentvirtualdesktops,intheupperleft-handcornerofaprogramwindowlookforaniconthatlookslikeapushpin.Pressingthisbuttonwill“pin”thatapplicationinplace,makingitappearinallvirtualdesktops,inthesamepositiononscreen.
ANSWER
QUESTION 37
39. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatcommandshouldyouusetocheckthenumberoffilesanddiskspaceusedbyeachuser'sdefinedquotas?
39
QUESTION
Thecommand'repquota'comestorescuehere.Commandrepquotasummariesquotasforafilesystem.
ANSWER
QUESTION 38
40. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whataredaemons?
40
QUESTION
Daemonsareservicesthatprovideseveralfunctionsthatmaynotbeavailableunderthebaseoperatingsystem.Itsmaintaskistolistenforservicerequestandatthesametimetoactontheserequests.Aftertheserviceisdone,itisthendisconnectedandwaitsforfurtherrequests.
ANSWER
QUESTION 39
41. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Youhavelotsofrunningjobs,howwouldyouremovealltherunningprocesses,withoutrestartingthemachine?
41
QUESTION
TheLinuxcommand'disown-r'willremovealltherunningProcesses.
ANSWER
QUESTION 40
42. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
AuserisnewtoLinuxandhewantstoknowfulllistofavailablecommands,whatwouldyousuggesthim?
42
QUESTION
Acommand'compgenc'willshowafulllistofavailablecommands.
[root@localhost~]$compgen-c
l.
ll
ls
which
if
then
else
elif
fi
case
esac
for
select
while
until
do
done
…
ANSWER
QUESTION 41
43. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatarethekindsofpermissionsunderLinux?
43
QUESTION
Thereare3kindsofpermissionsunderLinux:
-Read:usersmayreadthefilesorlistthedirectory
-Write:usersmaywritetothefileofnewfilestothedirectory
-Execute:usersmayrunthefileorlookupaspecificfilewithinadirectory
ANSWER
QUESTION 42
44. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Youneedtotrackeventsonyoursystem.Whatwillyoudo?
44
QUESTION
Fortrackingtheeventsonthesystem,weneedadaemoncalledsyslogd.Thesyslogddaemonisusefulintrackingtheinformationofsystemandthensavingittospecifiedlogfiles.
Running„syslogd„applicationinterminalgenerateslogfileatthelocation„/var/log/syslog„.ThesyslogdapplicationisveryusefulintroubleshootingLinuxsytems.Asamplelogfilelookssimilartobelow.
ANSWER
QUESTION 43
45. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowwillyourestrictIPsothattherestrictedIP‟smaynotusetheFTPServer?
45
QUESTION
WecanblocksuspiciousIPbyintegratingtcp_wrapper.Weneedtoenabletheparameter“tcp_wrapper=YES”intheconfigurationfileat„/etc/vsftpd.conf‟.AndthenaddthesuspiciousIPinthe„host.deny‟fileatlocation„/etc/host.deny‟.
ANSWER
QUESTION 44
46. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatarethedifferentmodeswhenusingvieditor?
46
QUESTION
Thereare3modesundervi:
-Commandmode–thisisthemodewhereyoustartin
-Editmode–thisisthemodethatallowsyoutodotextediting
-Exmode–thisisthemodewhereinyouinteractwithviwithinstructionstoprocessafile
ANSWER
QUESTION 45
47. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Isitpossibletouseshortcutforalongpathname?
47
QUESTION
Yes,thereis.AfeatureknownasfilenameexpansionallowsyoudothisusingtheTABkey.Forexample,ifyouhaveapathnamed/home/iceman/assignmentsdirectory,youwouldtypeasfollows:/ho[tab]/ice[tab]/assi[tab].This, however,assumesthatthepathisunique,andthattheshellyou‟reusingsupportsthisfeature.
ANSWER
QUESTION 46
48. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
TellusthedifferencebetweenTelnetandSSH?
48
QUESTION
TelnetandSSHbotharecommunicationprotocolwhichareusedtomanageremotesystem.SSHisSecured,whichrequiresexchangingofkeyoppositeoftelnetwhichtransmitdatainplaintext,whichmeanstelnetislesssecurethanSSH.
ANSWER
QUESTION 47
49. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
YouneedtostopyourXserver.WhenyoutriestokillyourXserver,YougotanerrormessagethatyoucannotquitXserver.Whatwillyoudo?
49
QUESTION
WhenkillingaXserver,itwon‟tworknormalwaylikedoing„/etc/init.d/gdmstop‟.Weneedtoexecuteaspecialkeycombination„Ctrl+Alt+BackSpace‟whichwillforceXservertorestart.
ANSWER
QUESTION 48
50. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisthedifferencebetweencommand„ping‟and„ping6′?
50
QUESTION
Boththecommandsaresameandusedforthesamepurposeexceptthatthefactthatping6isusedwithipv6IPaddress.
ANSWER
QUESTION 49
51. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisredirection?
51
QUESTION
Redirectionistheprocessofdirectingdatafromoneoutputtoanother.Itcanalsobeusedtodirectanoutputasaninputtoanotherprocess.
ANSWER
QUESTION 51
52. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Youwanttosearchforallthe*.tarfilesinyourHomedirectoryandwantstodeleteallatonce.Howwillyoudoit?
52
QUESTION
Weneedtousefindcommandwithrmcommandtodeleteall“.tar”files.
#find/home/name'*. tar'|xargsrmrf
ANSWER
QUESTION 51
53. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisthedifferencebetweenlocateandslocatecommand?
53
QUESTION
Theslocatelooksforthefilesthatuserhaveaccesswhereaslocatewillsearchforthefilewithupdatedresult.
ANSWER
QUESTION 52
54. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatistheSMTP?
54
QUESTION
SMTPisthemostcommonprotocolforane-mailserver.
ANSWER
QUESTION 53
55. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatSambaservicedo?
55
QUESTION
TheSambaserviceprovidesMicrosoftSMBsupportinLinuxsothatLinuxmachinescanconnecttoMicrosoftnetworkresources.
ANSWER
QUESTION 54
56. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhichservicecanbeusedwithNFStoprovideremotefileaccessforUNIXsystems?
56
QUESTION
NISisusedwithNFStoprovideremotefileaccessforUNIXsystems.
ANSWER
QUESTION 55
57. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisMTA?
57
QUESTION
MTAisaserviceofSendmailserver,whichtransfermailfromonenetworkorhosttoanothernetworkorhost.
ANSWER
QUESTION 56
58. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Nameaconnection-lessprotocolforfiletransfer.
58
QUESTION
TFTPisaconnection-lessprotocolforfiletransfer.
ANSWER
QUESTION 57
59. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Youcompanyhaveslowinternetconnection.WhichLinuxserviceyoucanusetomanageinternetconnection?
59
QUESTION
YoushoulduseSquidproxyserver,whichallowstomanagethewebcontentsandalsocachethewebpagestodecreasetheamountoftrafficgoingtoInternet.
ANSWER
QUESTION 58
60. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whichportshouldyouopeninyourhostfirewalltorunwebserver?
60
QUESTION
Bydefaultwebserveruseport80and443whichyouneedtoopeninfirewall.
ANSWER
QUESTION 59
61. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhichIPaddressingshouldyouuseforServer?
61
QUESTION
ForserveryoushouldalwaysusestaticIPaddress.
ANSWER
QUESTION 60
62. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whichportsshouldyouopeninhostfirewallforanemailserver?
62
QUESTION
Openport110whichisusedbythePOP3e-mailprotocol.
Openport25whichisusedbytheSMTPe-mailprotocol.
Openport143whichisusedbytheIMAPe-mailprotocol.
ANSWER
QUESTION 61
63. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhichIPaddressshouldyouuseforclientdesktop?
63
QUESTION
Forclientyoucanusebothstaticanddynamicmethod.ForeasymanagementusingDHCPtoassignIPaddresswouldbethebestoption.
ANSWER
QUESTION 62
64. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisinitrdimageandwhatisitsfunctioninthelinuxbootingprocess?
64
QUESTION
TheinitialRAMdisk(initrd)isaninitialrootfilesystemthatismountedpriortowhentherealrootfilesystemisavailable.Theinitrdisboundtothekernelandloadedaspartofthekernelbootprocedure.Thekernelthenmountsthisinitrdaspartofthetwo-stagebootprocesstoloadthemodulestomaketherealfilesystemsavailableandgetattherealrootfilesystem.Thusinitrdimageplaysavitalroleinlinuxbootingprocess.
ANSWER
QUESTION 63
65. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Explainthetermssuid,sgidandstickybit?
65
QUESTION
InadditiontothebasicfilepermissionsinLinux,therearefewspecialpermissionsthatareavailableforexecutablefilesanddirectories.
SUID:Ifsetuidbitisset,whenthefileisexecutedbyauser,theprocesswillhavethesamerightsastheownerofthefilebeingexecuted.
SGID:Sameasabove,butinheritsgroupprevilegesofthefileonexecution,notuserprevileges.Similarwaywhenyoucreateafilewithindirectory,itwillinheritthegroupownershipofthedirectories.
Stickybit:Stickybitwasusedonexecutablesinlinuxsothattheywouldremaininthememorymoretimeaftertheinitialexecution,hopingtheywouldbeneededinthenearfuture.Butmainlyitisonfolders,toimplythatafileorfoldercreatedinsideastickybitenabledfoldercouldonlybedeletedbytheowner.Averygoodimplementationofstickybitis/tmp,whereeveryuserhaswritepermissionbutonlyuserswhoownafilecandeletethem.
ANSWER
QUESTION 64
66. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
ListoutfewofthedifferencesbetweenSoftlinkandHardlink?
66
QUESTION
a)Hardlinkcannotbecreatedfordirectories.Hardlinkcanonlybecreatedforafile.
b)Symboliclinksorsymlinkscanlinktoadirectory.
c)Removingtheoriginalfilethatyourhardlinkpointstodoesnotremovethehardlinkitself;thehardlinkstillprovidesthecontentoftheunderlyingfile.
d)Ifyouremovethehardlinkorthesymlinkitself,theoriginalfilewillstayintact.
e)Removingtheoriginalfiledoesnotremovetheattachedsymboliclinkorsymlink,butwithouttheoriginalfile,thesymlinkisuseless
ANSWER
QUESTION 65
67. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisthedifferencebetweenumaskandulimit?
67
QUESTION
umaskstandsfor„Userfilecreationmask‟,whichdeterminesthesettingsofamaskthatcontrolswhichfilepermissionsaresetforfilesanddirectorieswhentheyarecreated.Whileulimitisalinuxbuiltincommandwhichprovidescontrolovertheresourcesavailabletotheshelland/ortoprocessesstartedbyit.
Youcanlimitusertospecificrangebyediting/etc/security/limits.confatthesametimesystemwidesettingscanbeupdatedin/etc/sysctl.conf
ANSWER
QUESTION 66
68. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthefunctionalityofaPuppetServer?
68
QUESTION
Puppetisanopen-sourceandenterpriseapplicationforconfigurationmanagementtollinUNIXlikeoperatingsystem.PuppetisanITautomationsoftwareusedtopushconfigurationtoitsclients(puppetagents)usingcode. Puppetcodecandoavarietyoftasksfrominstallingnewsoftware,tocheckfilepermissions,orupdatinguseraccountsandlotsofothertasks
ANSWER
QUESTION 67
69. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisSeLinux?
69
QUESTION
SELinuxisanacronymforSecurity-enhancedLinux.ItisanaccesscontrolimplementationandsecurityfeaturefortheLinuxkernel.Itisdesignedtoprotecttheserveragainstmisconfigurationsand/orcompromiseddaemons.Itputlimitsandinstructsserverdaemonsorprogramswhatfilestheycanaccessandwhatactionstheycantakebydefiningasecuritypolicy.
ANSWER
QUESTION 68
70. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Explainbrieflytheprocedureforre-installingGrubinLinux?
70
QUESTION
1)DownloadUbuntuInstallation/Livecd
2)BootfromUbuntuInstallation/Livecd-usb,burnedcdetc.
3)Duringbootselect“TryUbuntu”,Don‟tselectinstall!
4)MountyourLinuxrootpartition
sudomount/dev/sda6/mnt(Assuming/dev/sda6istheLinuxrootpartition)
5)Install/reinstallgrub
$sudogrub-install--root-directory=/mnt//dev/sda(where/dev/sdaisyourprimarydisk)
Installationfinished.Noerrorreported.
6)Rebootyoursystem,removebootableCDandweshouldhavethebootmenureadywhenthesystemstarts.
Note:Therewouldbeslightdifferencewhenusingwithotherdistros
ANSWER
QUESTION 69
71. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
ExplainthedifferentScenariosinvolvedinTCP3wayhandshake?
71
QUESTION
TheTCPthreewayhandshakeistheprocessforestablishingaTCPconnection.Wecanexplain3wayhandshakewithasimplescenariowhereweassumeaclientcomputeriscontactingaservertosenditsomeinformation.
a)TheclientsendsapacketwiththeSYNbitsetandasequencenumberofN.
b)TheserversendsapacketwithanACKnumberofN+1,theSYNbitsetandasequencenumberofX.
c)TheclientsendsapacketwithanACKnumberofX+1andtheconnectionisestablished.
d)Theclientsendsthedata.
Thefirstthreestepsintheaboveprocessiscalledthethreewayhandshake.
ANSWER
QUESTION 70
72. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisrDNSandexplainitsbenefitsintheLinuxDomainNameSystems?
72
QUESTION
AtypicalDNSlookupisusedtodeterminewhichIPaddressisassociatedwithahostname,andthisiscalledForwardDNSlookup.AreverseDNSlookupisusedfortheopposite,todeterminewhichhostnameisassociatedwithanIPaddress.SometimesreverseDNSlookupsarerequiredfordiagnosticpurposes.Today,reverseDNSlookupsareusedmainlyforsecuritypurposestotraceahackerorspammer.Manymodernmailingsystemsusereversemappingtoprovidesimpleauthenticationusingduallookup:hostname-to-addressandaddress-to- hostname.TherDNS(reverseDNS)isimplementedusingaspecializedzonerecordforreverselookupscalledPTRrecord.PTRrecordsalwaysresolvetonames,neverIPaddresses.
ANSWER
QUESTION 71
73. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhyisLVMrequired?
73
QUESTION
LVMstandsforLogicalVolumeManager,toresizefilesystem‟ssizeonlinewerequiredLVMpartitioninLinux.SizeofLVMpartitioncanbeextendedandreducedusingthelvextend&lvreducecommandsrespectively.
ANSWER
QUESTION 72
74. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowtocheckMemorystatsandCPUstats?
74
QUESTION
Using„free‟&„vmstat‟commandwecandisplaythephysicalandvirtualmemorystatisticsrespectively.Withthehelpof„sar‟commandweseetheCPUutilization&otherstats.
ANSWER
QUESTION 73
75. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
HowtoincreasethesizeofLVMpartition?
75
QUESTION
BelowaretheLogicalSteps:
-Usethelvextendcommand(lvextend-L+100M/dev/<NameoftheLVMPartition>,inthisexampleweareextendingthesizeby100MB.
-resize2fs/dev/<NameoftheLVMPartition>
-checkthesizeofpartitionusing„df-h‟command
ANSWER
QUESTION 74
76. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Howtocreatepartitionfromtherawdisk?
76
QUESTION
Usingfdiskutilitywecancreatepartitionsfromtherawdisk.Belowarethestepstocreatepartitionfromtherawdsik:
-fdisk/dev/hd*(IDE)or/dev/sd*(SCSI)
-Typentocreateanewpartition
-Aftercreatingpartition,typewcommandtowritethechangestothepartitiontable.
ANSWER
QUESTION 75
77. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisloadaverageinalinux?
77
QUESTION
LoadAverageisdefinedastheaveragesumofthenumberofprocesswaitingintherunqueueandnumberofprocesscurrentlyexecutingovertheperiodof1,5and15minutes.Usingthe„top‟and„uptime‟commandwefindtheloadaverageofalinuxsever.
ANSWER
QUESTION 76
78. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatistheroleofudevdaemon?
78
QUESTION
Theudevdemonusedtocreateandremoveallthesedevicenodesorfilesin/dev/directory.
ANSWER
QUESTION 77
79. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisRAID?
79
QUESTION
RAID,standsforRedundantArrayofInexpensiveDisks.RAIDisamethodbywhichsamedataorinformationisspreadacrossseveraldisks,usingtechniquessuchasdiskstriping(RAIDLevel0),diskmirroring(RAIDLevel1), anddiskstripingwithparity(RAIDLevel5)toachieveredundancy,lowerlatency,increasedbandwidth,andmaximizedabilitytorecoverfromharddiskcrashes.
ANSWER
QUESTION 78
80. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisCUPS?WhatisthelocationoflogfilesforCUPS?
80
QUESTION
CUPSstandsfor"CommonUNIXPrintingSystem".CUPSisaopensourceprintingsystemdevelopedbyAppleInc. CUPSusestheInternetPrintingProtocol(IPP)toallowlocalprintingandprintsharing.
ThelogfilesfortheCUPSprintingsystemarelocatedinthe/var/log/cups/directory.
ANSWER
QUESTION 79
81. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisYUM?
81
QUESTION
YUMstandsforYellowdogUpdater,ModifiedbecauseitisbasedonYUP,theYellowdogUpdater.WheredoesthenameYellowdogcomefrom?YellowDogisaversionofLinuxforthePowerArchitecturehardwareandisRPM- based,justlikeRedHatEnterpriseLinuxandFedora.YUP,andlaterYUM,werewrittenbytheLinuxcommunityasawaytomaintainanRPM-basedsystem.
ANSWER
QUESTION 80
82. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Differentiaterelativepathfromabsolutepath.
82
QUESTION
Relativepathreferstothepathrelativetothecurrentpath.Absolutepath,ontheotherhand,referstotheexactpathasreferencedfromtherootdirectory.
ANSWER
QUESTION 81
83. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatispiping?
83
QUESTION
Piping,representedbythepipecharacter“|”,isusedtocombinetwoormorecommandstogether.Theoutputofthefirstcommandservesasinputthenextcommand,andsoon.
ANSWER
QUESTION 82
84. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisasuperuser?
84
QUESTION
Asuperuserisaspecialtypeuserwhohasopenaccesstoallfilesandcommandsonasystem.Notethatthesuperuser‟sloginisusuallyroot,andisprotectedbyaso-calledrootpassword.
ANSWER
QUESTION 83
85. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatistheuseoftheteecommand?
85
QUESTION
Theteecommanddoestwothings:oneistogetdatafromthestandardinputandsendittostandardoutput;thesecondisthatitredirectsacopyofthatinputdataintoafilethatwasspecified.
ANSWER
QUESTION 84
86. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisparsing?
86
QUESTION
Parsingistheprocessofbreakingupofacommandlineintowords.Thisismadepossiblebyusingdelimitersandspaces.Intheeventthattabsormultiplespacesarepartofthecommand,theseareeventuallyreplacedbyasinglespace.
ANSWER
QUESTION 85
87. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatispid?
87
QUESTION
PidisshortforProcessID.ItisusedprimarilytoidentifyeveryprocessthatrunsontheUNIXsystem,whetheritrunsontheforegroundorrunsatthebackground.Everypidisconsideredunique.
ANSWER
QUESTION 86
88. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisldd?
88
QUESTION
Listdynamicdependencies–printsharedlibrarydependencies
Eg:–#vimnew.c
#gccnew.c–onew
#lddnew
ANSWER
QUESTION 87
89. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhatisthecommandtouninstallprocessesinLinux?
89
QUESTION
rpm–esendmail
-e–remove
ANSWER
QUESTION 88
90. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WhataretheLinuxbootfiles?
90
QUESTION
1./boot/grub/grub.conf:containsbootdiskparameters
2./etc/fstab:containsFilesystemswhichneedtomountatboottime
3./etc/initab:Containsdefaultrunlevel
4./etc/init.d/rc.d/rcN.d:Thisisadiritcontains
ANSWER
QUESTION 89
91. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Differencebetweennfssoftandhardmountingpoints?
91
QUESTION
Hardmountoption:–Iftheclientfailstoaccesstheserver,thentheconnectionhangsandoncethesystemisupthenitwillagainaccesstheserver.
Soft:–Iftheclientfailedtoconnecttheserver,itimmediatelygivestheerrorreportandclosestheconnection.
ANSWER
QUESTION 90
92. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisthestatuscode403,404representedinapacheserver?
92
QUESTION
403representforbiddenerror,meansifafilemissessomeselinuxsecuritycontext.
404representthatthereisacgiscriptmissingorwebpagesmissing.
ANSWER
QUESTION 91
93. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
WHATISTHEMEANINGOFAIX
93
QUESTION
AIX(AdvancedInteractiveeXecutive)isanopenoperatingsystemfromIBMwhichisbasedonaversionofUNIX. AIX/ESAwasdesignedforIBM‟sSystem/390orlargeserverhardwareplatform.AIX/6000isanoperatingsystemthatrunsonIBM‟sworkstationplatform,theRISCSystem/6000.
ANSWER
QUESTION 92
94. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whoinventedunix?
94
QUESTION
Unixwascreatedin1969byKenThompsonandDennisRitchieatBellLaboratories.
ANSWER
QUESTION 93
95. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatisthecommandtomakeaprocesstorunintheforegroundfrombackground?
95
QUESTION
Whentheprocessisrunning,press“control+Z”.Nowatthecommandprompt,type“bg”
ANSWER
QUESTION 94
96. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Iwanttoseehowmanyinterfaces(Ethernetcards)areworkingusingsinglecommand?
96
QUESTION
Ifconfig
ANSWER
QUESTION 95
97. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Afilewhichisnotdeletedbynormaluserandalsoroot(usingrm),forthattypeoffilehowwedeleteit?
97
QUESTION
Usingchattrcommand,weneedtochangetheattributesandthenweremoveusingrmcommand.
Eg:–chattr-iIuexample
rm-rfexample
ANSWER
QUESTION 96
98. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatiswild-cardinterpretation?
98
QUESTION
Whenacommandlinecontainswild-cardcharacterssuchas„*‟or„?‟,thesearereplacedbytheshellwithasortedlistoffileswhosepatternmatchestheinputcommand.Wild-cardcharactersareusedtosetupalistoffilesforprocessing,insteadofhavingitspecifiedoneatatime.
ANSWER
QUESTION 97
99. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Whatdoesthiscommanddo?catfood1>kitty
99
QUESTION
Itredirectstheoutputofcatfoodintothefilekitty;thecommandisthesameas:
catfood>kitty
ANSWER
QUESTION 98
100. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
What"neat"commandwilldo?
100
QUESTION
“Neat”commandprovidesGraphicalinterfacetochangenetworksettingsfornetworkdevices.
ANSWER
QUESTION 99
101. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Isthereanyrelationbetweenmodprobe.conffileandnetworkdevices?
101
QUESTION
Yes,thisfileassignsakernelmoduletoeachnetworkdevice.
ForExample:-
[root@localhost~]#cat/etc/modprobe.conf
aliaseth0b44
Hereb44isthekernelmodulefornetworkdeviceeth0.
WecanConfirmbyfollowingcommand(Thismodule“b44”ispresentornot).
[root@localhost~]#lsmod|grepb44
b44290050
ANSWER
QUESTION 100
102. For the hottest LINUX jobs, please visit www.hirist.com
hirist
.com
Resources
102
https://www.udemy.com/blog/linux-interview-questions/
http://www.masteringinlinux.com/linux-questions/top-linux-interview-question- answer.html
http://computernetworkingnotes.com/rhce-interview-questions/basic-linux- interview-questions-for-freshers.html
http://www.tecmint.com/core-linux-interview-questions-and-answers/
http://www.linuxtechi.com/experience-linux-admin-interview-questions/
http://www.01world.in/p/linux.html
http://linoxide.com/linux-how-to/linux-interview-questions-answers/
http://career.guru99.com/top-50-linux-interview-questions/
http://www.tecmint.com/useful-random-linux-interview-questions-and-answers/
http://certcollection.org/forum/topic/154299-linux-system-administration- interview-questions-and-answers/
http://linuxserverworld.com/linux-interview-questions-part-i/