南开大学UNIX管理与开发期末试卷PAGE9/NUMPAGES9南开大学2013——2014年度第二学期《Unix管理与开发》期末考试试卷(考试时间：100分钟总分100分)院（系）软件
工程
路基工程安全技术交底工程项目施工成本控制工程量增项单年度零星工程技术标正投影法基本原理
学号姓名分数一．选择正确的答案（每题2分，共20分）1.Thesignsoffilescanberead,write,executearefollowedinturn(A)。A.rwxB.xrwC.rdxD.srwAnswer:A2.Exitinteractiveshell，shouldinput(C)。A.
;B.^qC.exitD.quitAnswer:C3.Ifsuperuserrootwasunderthedirectory：/usr/local，afterinputcd，theuserisunderwhichdirectorynow(B)。A./homeB./rootC./home/rootD./usr/localAnswer:B4.Thereisafilenamedfileunderthedirectory:/home/stud1/wang，using(C)canmakeitruninthebackground，thecommandoutputthecontentoffiletofile.copyA.catfile>;file.copyB.cat>;file.copyC.catfilefile.copy&D.catfile>file.copy&Answer:C5.InUNIXsystem，thesourcefilechangestoexecutablefilethroughcompiling,theexecutablefilebelongsto(B)A.ASCIIfileB.ordinaryfileC.directoryfileD.specialfileAnswer:B6.ThefollowingnarrativeonUNIX,whichisnotcorrect(C)A.UNIXfilesystemisatreestructure,easytomanageandretrieveB.UNIXprovidesawealthofsoftwaretools,suchasutilities,text,anddevelopmenttoolsC.UNIXmanagesordinaryfiles,directories,files,anddevicefilesindifferentwaysD.UNIXisamulti-user,multi-taskingoperatingsystemAnswer:C7.IfyouwanttoknowthedetailusageoffindwhichisacommandofUnix,youshouldinput（C）A．helpfindB．findhelpC．manfindD．findmanAnswer:C8.Aboutthecommandcp，whichisincorrect（C）A．cpfile1file2B．cpfile1file2/tmpC．cp–rfile1file2D．cp–r/tmp/mytmpAnswer:C9.Whenwecreateanewfile,ithaspropertiesasfollowed（A）A．ReadableandwritablepropertyB．ReadableexecutablepropertyC．WritableexecutablepropertyD.Read-writeexecutablepropertyAnswer:A10.Ifwewanttochangethetimeofafile,usethecommand（C）A．timeB.DateC.touchD.calAnswer:C11.Aboutthecommandcd,whichisincorrect（D）A．cdBacktodirectorywhenregisteringB．cd/tmpintodirectory/tmpC．cd../intotheupperdirectoryD．cd./intotherootdirectoryAnswer:D12.Whenyoucreateanewdirectoryusingthemkdircommand,theoptionwhenitsparentdirectoriesdonotexisttocreateaparentdirectoryis(D)。 A. -m B. -d C. -f D. –pAnswer:DThefollowingstatements,whichisnotbelongtothescopeoftheroleoftheifconfigcommand(D)。A.ConfigurethelocalloopbackaddressB.ConfiguretheIPaddressofthenetworkcardC.ActivatethenetworkadapterD.LoadthecardintothekernelAnswer:DTherearefourmethodstoassignmentofvariablesintheshell，thenameofname=12is(A)。A.DirectassignmentB.UsereadcommandC.UsingthecommandlineparametersD.UsethecommandoutputAnswer:A15.Changetheownerofafile,usecommand(C)。A.chmodB.touchC.chownD.catAnswer:Chowmany“-”willoutputinthefollowingprocedures?(D)#include#include#includeintmain(){for(inti=0;i<2;i++){fork();printf("-");}return0;}A.2B.4C.6D.8Answer:D17.Thefollowingdescriptionoftheerrorthatrespecttothei-nodeis（A）.A.inodeandfileisonetooneB.inodecandescribethenumberofblocksthatoccupiedbythefileC.i-nodedescribesthesizeofthefileandapointerpointingtothedatablocksD.Achievetransformationofthelogicandphysicalstructureofthedocumentbythei-nodeAnswer:A18.Permissionsoftheoutsidemembersofgroupofafileisread-only;theownerhasfullpermissions;permissionswithinthegrouptoreadandwrite,thenthefilepermissionsis(D)A. 467 B. 674 C. 476 D. 764 Answer:D19.Howtodisplaythecurrentdirectory（A）.pwdB.cdC.whoD.IsAnswer:A20.Whichisthereturnvalueoftheexitcommandinscript,saidthescriptsuccessfully(D)A、1B、-1C、2D、0Answer:D21.whichcommandisusedofChangingPassword（B）A、whoB、passwdC、passwordD、pwdAnswer:B22.Processsynchronizationreferstotherelationshipbetweentheprocessofmutual（B）inlogicA、ConnectionB、restraintC、continueD、CallingAnswer:B24.Howsettheshellscriptexam.shasalluserscanexecute（A）A、chomda+xexam.shB、chomda+wexam.shC、chomda+rexam.shD、chomdu+wexam.shAnswer:A25.Managementandcontrolprocessesby（B）A、InstructionB、PrimitiveC、SemaphoreD、MailcommunicationAnswer:B26.The command used to change the name of file of directory is（C）A、rmB、cpC、mvD、cdAnswer:C27.TocompileaCprogram,enter(D)incommandprompt.A、cprgnameB、cc–ocprgnameC、ccccprgnameD、cccprgname二．判断题（每题2分，共10分）（√）Liketheshell,theoutputthatisgeneratedbyprintandprintfcanbedirectedtoafileorpipe.Answer:True（√）ItisnotnecessarythattheschedulerallocatesCPUtotheprocess.Answer:True（×）Whenencrypted,thecommandcanspecifymultiplefilesasfiles,andthecommandencryptedallthefiles.Answer:False（×）UDPprotocolisaconnectionlessprotocol,sothathecanprovidereliabledatatransmission.Answer:False（×）Processisacollectionofinstructions.Answer:False三．填空题（每题2分，共10分）1.Thefilesanddirectoriestopackagecommandis____tar___Answer：tar2.Thecommandtoendthebackgroundprocessis__kill__Answer：killUse__diff__commandtocomparethedifferentbetweentwocontentsoffiles.Answer：diff__stdin__、__stdout__、_stderr__will be opened at the beginning of the creation of aLINUXprocesses.Answer：stdin、stdout、stderrListseveralmaindirectoryofUNIX/boot/etc/dev/bin/user/homeAnswer：/boot/etc/dev/bin/user/home6.TheTestcommandcantest__file__,__integer__,__string__.Answer：file、integer、string四．简答题（每题8分，共40分）Inthe UNIX operatingsystem are classified in thetypesof operatingsystems? Whatarethemain featuresofUNIX systems?Answer:1．UNIX isa multi-tasking multi-user time-sharingsystem,therequest time astheunitto respondtomultipleusers.Features:The simpledesign andmethods toaccomplish morecomplex, morecomprehensivefunctionality.Supportmulti-user multi-taskingoperatingenvironment filesystems caneasily handling opennessand goodportabilitypowerfulcommand-featured security mechanismof networkcharacteristics.2.What'stheinterprocesscommunication?List3toolsprovidedbyUNIXforinterprocesscommunication.Answer:(1)TheinterprocesscommunicationistransferringdatabetweendifferentUNIXcommands.(2)Threetools:pipeline,commandpipelineandsocket.3.DescribeseveraloperationallevelsandtheircorrespondingmeaningsofLinux.Answer: 0-shutdownmode, 1-single-usermode,onlythesystemadministratorcanlogonsingle-usermode. 2-multi-usermode,butdoesnotsupportfilesharing,forexample,doesnotsupportNFSservices.Thismodelisnotcommonlyused. 3-completemulti-usermode,supportforNFSservice.Themostcommonusermode,logontothecharacter-basedinterfaceofthesystemdefaultly. 4-retainedmode. 5-fullymulti-usermode,logontotheX-windowsystemdefaultly,whichisloggedontothelinuxgraphicalinterface.6-restartmode,whichisexecutedtocloseallrunningprocesses,thenrestartthesystem.4.Whatisthelink?Whatisthedifferencebetweensymboliclinkandhardlink?Answer:Linkreferstoani-nodecorrespondstomultiplefilenames.Ahardlinkislettingthei-nodenumberofthefilepointtothei-node,andthecountervalueofthelinkisincremented1.Whenyoudeletealinkofafile,countervaluedecreased1.whenitsvalueis0,inodeisreleased.Asymboliclinkisonlyalinkfile,whichonlyhasaname,doesnotpointtoarealnodei.Whenyoudeleteasymboliclinkofafileyoucanfindoutthatisdifferentfromahardlinkfiles.5.Thedifferencebetweenforkandvfork.Answer:1)forkneedcopythedatasegmentoftheparentprocess;Whilethevforkdoesn’tneedtocopythedatasegmentofparentprocesscompletely,thesonprocessandtheparentprocessshareddatasegmentbeforethesonprocessdoesn’tcallexecandexit.2)forkdoesn’tmakeanyrestrictionstotheexecutionorderofthesonprocessandparentprocess;andinthevfordcall,thesonprocessfirsttorun,theparentprocesshang,afterthesonprocesscallsexecorexit,theexecutionorderoftheparentandsonprocesshasnolongerlimit.6.Descriptionthecharacteristicsoftheshell.Answer:Shellisaninteractivecommandinterpreter,andisalsoakindofprogramminglanguage.Eachstatementofitisexecutablecommand.Shelltosatisfytheinteractivecommandandprogrammingoperationcommandtwowaysofusingrequirements,isakindofspeciallanguage.Itsapplicationrangeiswide,andhashighoperationefficiency.7.WhattechnologydoesUnixusetoreadandwritepiecesofequipmentoperation?Answer:UNIXblockdeviceisrealizedbyusingbuffertechnologytoreadandwriteoperations.Driverallocateabufferforwriteoperation,firsttheinformationfromtheuserspaceiscopiedtothebuffer,andoutputfrombuffertothedevice;Toreadoperation,toreceiveinformationfromthedevicetothebuffer,thentheinformationiscopiedtothespecifieduserspace.Usingbuffertechnologytoreducenumberofvisitstothepieceofequipmentcanimprovethethroughputofthesystem.8.Ifyouopenafileforread-writewiththeappendflag,canyoustillreadfromanywhereinthefileusinglseek?Canyouuselseektoreplaceexistingdatainthefile?Answer:Youcanstilllseekandreadanywhereinthefile,butawriteautomaticallyresetsthefileoffsettotheendoffilebeforethedataiswritten.Thismakesitimpossibletowriteanywhereotherthanattheendoffile.五．程序设计题（每题10分，共20分）1.DescribestheUnixnetworkprogrammingstepsanddescribeshowUnixcommunications.Answer:Webapplicationsandordinaryprogramhasoneofthebiggestdifferenceisthatthenetworkapplicationiscomposedoftwoparts-theclientandserver.Networkprogramisthefirstserverstartup,waitingfortheclientprogramrunningandestablishingtheconnection.Usuallytheprogramingenerallisteningonaport,untilthereisaclientprogramsentarequest.UNIXsystemisprovidedbythesocketfornetworkprogramming.Webapplicationthroughasocketandafewotherfunctioncalls,returnsacommunicationfiledescriptor.Wecanputthisdescriptorasanormalfiledescriptortooperate.ThisistheUNIXdevice’sindependence.Wecandoreadingandwritingoperationonthedescriptortoachievenetworkcommunication.2.Oncewehaveestablishedaconnection,thenextstepistocommunicate.Wetakethechannelwesettingupbeforeasafiledescriptor,sothattheserverandclientcouldcommunicate,aslongasthefiledescriptor,speaking,readingandwritingcontents.Justlikewereadandwritetothefile.2.程序阅读a.out:#include“apu.h”Intglobvar=6;Charbur[]=“awritetostdour\n”;Intmain(void){Intvar;Pid_tpid;Var=88;If(write(STDOUT_FILENO,buf,sizeof(buf)–1,)!=sizeof(buf)–1)Err_sys(“writeerror”);Printf(“beforefork\n”);If((pid=fork())<0){Err_sys(“forkerror”);}elseif(pid=0){Globvar++;Var++;}else{Sleep(2);}Printf(“pid=%ld,glob=%d,var=%d\n”,(long)getpid(),globvar,var);Exit(0);}executewiththiscommandandoccouranerror,willtherebeerroroutput?:$./a.out2>&1>outfileexecutewiththiscommandandsuccess,writetheoutputofscreen(ifthereis):$./a.out>outfile2>&1$catoutfileAnswer：No2awritetostdoutbeforeforkpid=432,glob=7,var=89beforeforkpid=431,glob=6,var=88
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