unix basics(the unix file system)课件

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1、Lecture2UNIXBasicsTheUNIXFilesystemOnthelastepisodeofOpenSourceTools…CourseInfoHistoryofUNIXandOpenSourceHighlightsofUNIXTheUNIXPhilosophySystemorganizationUnixSystemStructureusershellandutilitieskernelhardwarecprogramsscriptslsshgccfindopen()fork()exec()KernelSubsystemsFilesystemDealswith

2、allinputandoutputIncludesfilesandterminalsIntegrationofstoragedevicesProcessmanagementDealswithprogramsandprograminteractionHowprocessesshareCPU,memoryandsignalsSchedulingInterprocessCommunicationMemorymanagementUNIXvariantshavedifferentimplementationsofdifferentsubsystems.Whatisashell?Theuseri

3、nterfacetotheoperatingsystemFunctionality:ExecuteotherprogramsManagefilesManageprocessesAprogramlikeanyotherExecutedwhenyoulogonMostCommonlyUsedShells/bin/shTheBourneShell/POSIXshell/bin/cshCshell/bin/tcshEnhancedCShell/bin/kshKornshell/bin/bashOpenSourcekshcloneBasicformofshell:while(readcomma

4、nd){parsecommandexecutecommand}ShellInteractiveUseWhenyoulogin,youinteractivelyusetheshell:CommandhistoryCommandlineeditingFileexpansion(tabcompletion)CommandexpansionKeybindingsSpellingcorrectionJobcontrolShellScriptingAsetofshellcommandsthatconstituteanexecutableprogramAshellscriptisaregul

5、artextfilethatcontainsshellorUNIXcommandsVeryusefulforautomatingrepetitivetaskandadministrativetoolsandforstoringcommandsforlaterexecutionSimpleCommandssimplecommand:sequenceofnonblanksargumentsseparatedbyblanksortabs.1stargument(numberedzero)usuallyspecifiesthenameofthecommandtobeexecuted.Anyr

6、emainingarguments:Arepassedasargumentstothatcommand.Argumentsmaybefilenames,pathnames,directoriesorspecialoptions(uptocommand)SpecialcharactersareinterpretedbyshellAsimpleexampleExecuteabasiccommandParsingacommandintoargumentsiscalledsplitting$ls–l/bin-rwxr-xr-x1rootsys43234Sep102008date$prompt

7、commandargumentsTypesofArgumentsOptions/FlagsConvention:-Xor--longnameParametersMaybefiles,maybestringsDependsoncommand$tar–c–v–farchive.tarmain.cmain.hGettingHelponUNIXman:displayentriesfromUNIXonlinedocumentationwhatis,aproposMa