Complete 2026 Guide to Redis Commands: Everything You Need to Know

Redis is a core component in large‑scale architectures. This guide provides a complete overview of Redis commands, grouped by functionality, with usage examples, expected results, performance considerations, and best‑practice advice.

1. Redis Command Classification Overview

Redis 常用命令
│
├── Key管理
│   ├── KEYS *
│   ├── EXISTS key
│   ├── DEL key
│   ├── EXPIRE key seconds
│   └── BGSAVE
├── String操作
│   ├── SET key value
│   ├── GET key
│   └── INCR key
├── Hash操作
│   ├── HSET key field value
│   ├── HGET key field
│   └── HGETALL key
├── List操作
│   ├── LPUSH key value
│   └── LRANGE key start stop
├── 性能排查
│   ├── INFO
│   ├── MONITOR
│   └── BGSAVE

2. KEYS – Query All Matching Keys

Purpose: View existing keys in Redis. KEYS * Example to query user‑related keys: KEYS user:* Result example:

1) user:1001
2) user:1002
3) user:1003

Note: KEYS is an O(N) operation; using it on large datasets can block Redis’s single thread. Recommended alternative: SCAN.

3. EXISTS – Check If a Key Exists

EXISTS user:1001

Result: (integer) 1 if the key exists, 0 otherwise.

Typical use case: cache‑hit detection.

if (redis.exists(key)) {
    return redis.get(key);
}

4. DEL – Delete a Key

DEL user:1001

Delete multiple keys: DEL key1 key2 key3 Result: (integer) indicating the number of keys removed.

5. EXPIRE – Set Key Expiration

EXPIRE user:1001 3600

Result: 1 (expiration set). Use TTL to view remaining time: TTL user:1001 Result example: 3500 seconds.

6. SET – Set String Value

SET name mike

Result: OK.

Set with expiration (seconds):

SET token abc123 EX 3600

EX

sets seconds, PX sets milliseconds.

7. GET – Get String Value

GET name

Result: "mike". Commonly used for cache reads.

8. INCR – Increment Counter

INCR page:view

First call returns 1, second 2, etc. Typical for page‑view or like counters.

9. HSET – Store Object in a Hash

HSET user:1001 name mike age 28

Advantages over plain strings: saves memory and allows field‑level updates.

10. HGET – Retrieve Hash Field

HGET user:1001 name

Result: "mike".

Retrieve all fields: HGETALL user:1001 Result example:

name mike
age 28

11. LPUSH – Push Message onto a List

LPUSH order_queue order1001

Insert another message: LPUSH order_queue order1002 List now holds order1002 then order1001. Used for message queues, task queues, and asynchronous processing.

12. LRANGE – View List Contents

LRANGE order_queue 0 -1

Result shows all items in order.

View first 10 items:

LRANGE order_queue 0 9

13. INFO – Inspect Redis Runtime Status

General information: INFO Memory details: INFO memory Client list: INFO clients Replication status: INFO replication These commands are essential for online troubleshooting and performance monitoring.