The Command-Line InterfaceCommand Line Versus Terminal Versus ShellWhy Do I Need the Command Line?Getting Started with the Command LineProtocols: A High-Level OverviewProtocol LayersTwo Protocols Plus AnotherBasic Internet ProtocolsData Security: Confidentiality, Integrity, and AvailabilityDevelopment Overview for ScriptingCommands and Built-insBasic Programmatic Constructs: Variables, Data, and Data TypesMaking Decisions with ConditionalsLoopingLists and ArraysSummary