Redis CLI の基礎

The redis-cli lets you talk to your Redis server directly — perfect for quick tests, debugging, and admin without writing any app code.

Connect by running redis-cli in your terminal. It defaults to 127.0.0.1 on port 6379 and drops you at a prompt ready for commands.

PING checks that the server is alive — type it and a healthy Redis replies PONG. Your simplest health check.

SET stores a string value under a key: SET key value. Like sticking a labeled note on the fridge — the example shows it returning OK.

GET retrieves a key's value: GET key. If the key doesn't exist, Redis returns (nil) instead.

Run SET on an existing key and it overwrites the old value — no confirmation prompt, so be careful. The example shows the value getting replaced.

DEL removes one or more keys: DEL key [key ...]. It returns how many keys were actually deleted.

EXISTS tells you if a key is present without fetching its value — returning 1 if it exists, 0 if not.

Redis does counters: INCR bumps a key's integer up by one, DECR drops it by one. A missing key starts at 0 before the operation.

What will be the final value of the key mycounter after executing these Redis CLI commands?

Recap: with the redis-cli you can connect, PING, SET and GET strings, overwrite keys, DEL them, check EXISTS, and run INCR/DECR counters.