What Is a Shell?Scope of This BookHistory of Unix ShellsThe Korn ShellFeatures of the Korn ShellGetting the 1993 Korn ShellInteractive Shell UseCommands, Arguments, and OptionsBuilt-in HelpFilesDirectoriesThe working directoryTilde notationChanging working directoriesSymbolic links to directoriesFilenames and WildcardsInput and OutputStandard I/OI/O RedirectionPipelinesBackground JobsBackground I/OBackground Jobs and PrioritiesniceSpecial Characters and QuotingQuotingBackslash-EscapingQuoting Quotation MarksContinuing LinesControl Keys