Intro & Setup: Overview

Redis is an in-memory key-value data structure server — it stores all data in RAM, which makes reads and writes extraordinarily fast. This module walks you through running Redis with Docker, opening a redis-cli session, and sending your first commands.

🎁 Run Redis in Docker first

Start a local Redis, then open its CLI:

docker run -d --name redis -p 6379:6379 redis:7-alpine
docker exec -it redis redis-cli

Leave this CLI open and paste each lesson's commands into it. (No Docker? Install Redis locally.)

What this module covers

Lesson	Topic
Intro & Setup: Overview	This page — what Redis is and the run → cli → command loop
What is Redis?	In-memory model, event loop, and common use cases
Run with Docker	Pulling the image, starting a container, persistence basics
Redis CLI	Connecting, navigating history, inline help
First Commands	PING, SET, GET, DEL, and the PONG you will always remember

The run → cli → command loop

Every Redis session follows the same three steps:

1. Start a Redis server (here, with Docker)
2. Connect to it with redis-cli
3. Send commands and read replies

Once your container is running (use the panel above), open a terminal and connect:

docker exec -it redis redis-cli

You will see the 127.0.0.1:6379> prompt. Try these commands right away:

127.0.0.1:6379> PING
PONG
127.0.0.1:6379> SET name "Redis"
OK
127.0.0.1:6379> GET name
"Redis"

PING
SET name "Redis"
GET name

Copy commands ⧉

🟥 Redis keeps data in memory — extremely fast

Because Redis never touches disk during a normal read or write, latency is measured in microseconds rather than milliseconds. A single server routinely handles hundreds of thousands of operations per second.

The trade-off is that RAM is finite and more expensive than disk. Redis addresses this with optional persistence (RDB snapshots and AOF logs) and eviction policies that remove the least-useful keys when memory fills up. You will explore both later in the course.

Where does Redis primarily store its data?

On disk (SSD) In memory (RAM) In a relational database In a distributed file system

What does Redis reply with when you send the PING command?

OK 1 PONG nil

Which command stores a value under a key in Redis?

PUT INSERT SET STORE

Submit

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