The Command Line Interface (CLI) allows for comprehensive configuration of the SCALANCE S615 device, mirroring the functionality of the Web Based Management (WBM). It enables remote configuration via Telnet. The CLI commands are organized into different modes, such as Privileged EXEC, Global Configuration, and specific configuration modes for interfaces, VLANs, IPSEC, Firewall, and more. Users can navigate these modes using commands like 'enable', 'configure terminal', 'end', and 'exit'. Basic operations include displaying configuration data, modifying settings, and managing network protocols.