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Cisco Certified Support Technician (CCST) Networking 100-150 v1.0 · Domain 5: Diagnosing problems

Cisco IOS basics: user vs privileged EXEC, `?` help and tab completion

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Last reviewed September 25, 2026 · Leer en español

Cisco IOS (Internetwork Operating System) and its close relatives like IOS XE run most Cisco routers and switches. You interact with it through a command-line interface (CLI) over console, SSH or Telnet. The CLI is organized into modes, each shown by a different prompt, and each allowing different commands.

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