Cisco IOS CLI & ROMMON: Modes, Shortcuts, and Password Recovery
Working reference for the Cisco IOS command-line. The mode hierarchy (User EXEC -> Privileged EXEC -> global config -> interface/router/line config), tab-complete and command abbreviation, the navigation shortcuts (Ctrl-A/E/W/U/R), output filtering with pipe (include / exclude / begin / section / redirect), the seven ping result codes, ROMMON access via terminal break sequence, and the standard four-step password recovery procedure (confreg 0x2142 - reset - copy startup to running - enable secret - config-register 0x2102). Pitfalls: forgetting to restore config-register, break sequence not transmitting, console baud-rate mismatches in ROMMON.