What function does pressing the Tab key have when entering a command in Cisco IOS?

• A. It completes the remainder of a partially typed word in a command.
• B. It aborts the current command and returns to configuration mode.
• C. It exits configuration mode and returns to user EXEC mode.
• D. It moves the cursor to the beginning of the next line.

Answer: (A)

Tab triggers command-line completion. It completes the rest of a partially typed word in a Cisco IOS command when the match is unique, speeding typing and reducing errors. For example, typing show ip in and pressing Tab can fill in the full command like show ip interface brief if that’s the only option starting with that prefix. If multiple commands share the same prefix, IOS may beep and show the possible matches or require more characters to disambiguate. You can also use a question mark for help to see available options.