Redis Cheatsheet: Docker & Essential Commands

🐳 1. Launch and Management via Docker

Using Docker is the cleanest way to launch a Redis instance in development or production.

Basic Launch (Ephemeral)

Ideal for quick tests or temporary caching. Data is lost when the container stops.

Bash

docker run --name my-redis -p 6379:6379 -d redis

Launch with Data Persistence

Uses appendonly mode to save data to your host disk and survive restarts.

Bash

docker run --name my-persistent-redis \
  -p 6379:6379 \
  -v /path/to/local/folder:/data \
  -d redis redis-server --appendonly yes

Launch with Password (Secured)

Bash

docker run --name my-secure-redis -p 6379:6379 -d redis redis-server --requirepass "MySuperStrongPassword"

Connect to the Redis CLI (from the container)

Once your container is running, use this command to open the Redis prompt (redis-cli) and type the commands below:

Bash

docker exec -it my-redis redis-cli
# If you set a password:
docker exec -it my-redis redis-cli -a "MySuperStrongPassword"

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🔑 2. Basic Commands (Keys & Strings)

Strings are the simplest data type in Redis (ideal for page or session caching).

Command	Usage Example	Description
SET	SET user:1 "Eric"	Stores the value “Eric” in the key “user:1”.
GET	GET user:1	Retrieves the value of the key “user:1”.
DEL	DEL user:1	Deletes the key and its value.
EXISTS	EXISTS user:1	Returns 1 if the key exists, 0 otherwise.
EXPIRE	EXPIRE session:99 3600	Sets a time-to-live of 3600 seconds (1h) for the key.
TTL	TTL session:99	Shows the remaining time (in seconds) before expiration. (-2 = no longer exists, -1 = never expires).
INCR / DECR	INCR views:article:42	Increments (or decrements) an integer by 1. Highly performant for counters.

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📦 3. Advanced Data Structures

Redis excels thanks to its complex data structures, which can be manipulated directly in memory.

Lists

Arrays of strings, sorted by insertion order. Perfect for queues or news feeds.

Command	Usage Example	Description
LPUSH / RPUSH	LPUSH tasks "email_welcome"	Adds a value to the left (start) or right (end) of the list.
LPOP / RPOP	LPOP tasks	Removes and returns the first (or last) element of the list.
LRANGE	LRANGE tasks 0 -1	Shows all elements in the list (from index 0 to the last index -1).
LLEN	LLEN tasks	Returns the size (number of elements) of the list.

Hashes

Ideal for storing structured objects (like a database row or a user profile).

Command	Usage Example	Description
HSET	HSET user:2 name "Doe" age 35	Assigns fields and values to the hash “user:2”.
HGET	HGET user:2 name	Retrieves the value of the “name” field for this hash.
HGETALL	HGETALL user:2	Retrieves all fields and values of this hash.
HDEL	HDEL user:2 age	Deletes a specific field in the hash.

Sets

Collections of unique, unordered elements. Perfect for managing tags, banned IPs, or checking membership.

Command	Usage Example	Description
SADD	SADD banned_ips "192.168.1.1"	Adds an element to the set (if it already exists, it is ignored).
SMEMBERS	SMEMBERS banned_ips	Lists all elements in the set.
SISMEMBER	SISMEMBER banned_ips "10.0.0.1"	Returns 1 if the element is part of the set, 0 otherwise.

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⚙️ 4. Administration and Utilities

Useful commands to monitor and clean your Redis instance.

Command	Description
PING	Connection test. Redis replies PONG if the server is online.
INFO	Shows detailed server statistics (memory used, clients, version…).
KEYS *	Lists all existing keys. ⚠️ Warning: Never use in production on a large database, it blocks the server (use SCAN instead).
FLUSHDB	Deletes all keys from the currently selected database.
FLUSHALL	Deletes absolutely all keys from all databases in the instance.
MONITOR	Shows all commands received by the server in real time. Handy for debugging in development.

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