Redis Commands Overview

Complete guide to Redis command organization and categories

Redis commands are organized into logical groups based on the data structures and operations they perform. This guide provides an overview of all command categories and how to navigate the Redis command reference.

Command Groups

Redis organizes commands into the following groups:

Data Structure Commands

String Commands

GET, SET, INCR, DECR, APPEND - Work with string values

List Commands

LPUSH, RPUSH, LPOP, LRANGE - Manage ordered collections

Set Commands

SADD, SMEMBERS, SINTER - Handle unique unordered collections

Sorted Set Commands

ZADD, ZRANGE, ZRANK - Manage sorted collections with scores

Hash Commands

HSET, HGET, HGETALL - Store field-value pairs

Stream Commands

XADD, XREAD, XGROUP - Process append-only logs

System Commands

Generic Commands

DEL, EXISTS, EXPIRE - Work with keys of any type

Server Commands

INFO, CONFIG, SAVE - Manage server operations

Pub/Sub Commands

PUBLISH, SUBSCRIBE - Implement messaging patterns

Cluster Commands

CLUSTER NODES, CLUSTER SLOTS - Manage cluster topology

Scripting Commands

EVAL, EVALSHA, SCRIPT LOAD - Execute Lua scripts

Command Properties

Each Redis command has specific properties that affect its behavior:

Time Complexity

All commands document their computational complexity using Big O notation:

• O(1): Constant time - operations like GET, SET
• O(N): Linear time - operations like DEL with multiple keys
• O(log N): Logarithmic time - operations on sorted sets like ZADD
• O(N*M): Combined complexity - operations like SINTER

Command Flags

Commands are marked with flags indicating their characteristics:

• READONLY: Does not modify data
• WRITE: Modifies data
• FAST: Executes in constant or logarithmic time
• DENYOOM: Denied when memory is full
• STALE: Can run on stale replicas

ACL Categories

Commands belong to ACL categories for access control:

• KEYSPACE: Key management operations
• STRING: String data type operations
• LIST: List data type operations
• SET: Set data type operations
• SORTEDSET: Sorted set operations
• HASH: Hash data type operations
• STREAM: Stream data type operations
• PUBSUB: Publish/Subscribe operations
• SCRIPTING: Lua scripting
• DANGEROUS: Potentially dangerous operations

Command Naming Conventions

Redis follows consistent naming patterns:

Prefix Patterns

• L/R: Left/Right operations (LPUSH, RPUSH)
• B: Blocking variants (BLPOP, BRPOP)
• P: Pattern-based operations (PSUBSCRIBE)
• X: Stream operations (XADD, XREAD)
• Z: Sorted set operations (ZADD, ZRANGE)
• H: Hash operations (HSET, HGET)
• S: Set operations (SADD, SMEMBERS)

Suffix Patterns

• BY: Sort or compare (SORT, ZRANGEBYSCORE)
• STORE: Store result (SINTERSTORE)
• LEN: Get length (STRLEN, LLEN)
• NX/XX: Conditional operations (only if Not eXists / only if eXists)

Using the Command Reference

Each command page includes:

1. Syntax: Complete command syntax with all options
2. Parameters: Detailed parameter descriptions
3. Return Value: What the command returns
4. Time Complexity: Performance characteristics
5. Examples: Practical usage with redis-cli
6. History: Version changes and new features

Quick Reference

Most Common Commands

Command	Group	Purpose
GET	String	Retrieve string value
SET	String	Store string value
DEL	Generic	Delete keys
EXISTS	Generic	Check key existence
EXPIRE	Generic	Set key expiration
LPUSH	List	Add to list head
SADD	Set	Add to set
ZADD	Sorted Set	Add to sorted set
HSET	Hash	Set hash field
XADD	Stream	Add stream entry

Command History

Redis commands evolve over versions. Key milestones:

• Redis 1.0.0: Core data structures (strings, lists, sets)
• Redis 2.0.0: Hashes, pub/sub
• Redis 2.6.0: Lua scripting (EVAL)
• Redis 2.8.0: Pattern scanning (SCAN)
• Redis 3.0.0: Redis Cluster
• Redis 3.2.0: GEO commands
• Redis 5.0.0: Streams (XADD, XREAD)
• Redis 6.0.0: ACL system
• Redis 7.0.0: Redis Functions

Best Practices

Always check command time complexity before using in production. Commands like KEYS with O(N) complexity can block the server.

Performance Tips

1. Use SCAN instead of KEYS for production key iteration
2. Pipeline multiple commands to reduce round trips
3. Avoid blocking commands in high-throughput applications
4. Use appropriate data structures for your use case
5. Set expiration times to manage memory automatically

Security Considerations

1. Enable ACLs to restrict command access
2. Avoid DANGEROUS category commands in user-facing applications
3. Validate input before passing to EVAL scripts
4. Use connection limits to prevent resource exhaustion

Getting Help

Redis provides built-in help:

redis-cli> COMMAND INFO GET
redis-cli> COMMAND DOCS GET
redis-cli> HELP @string

Next Steps

Generic Commands

Learn key management operations

String Commands

Master the most common data type