Redis Cheat Sheet — Commands, Data Types, and Common Patterns

redis-cli                          # Connect to localhost:6379
redis-cli -h myhost -p 6380       # Custom host/port
redis-cli -a mypassword            # With password
redis-cli --tls                    # TLS connection
redis-cli ping                     # Test connection → PONG
redis-cli info                     # Server info
redis-cli monitor                  # Watch all commands in real-time

SET name "Alice"
GET name                  # "Alice"
DEL name                  # Delete key
SETNX name "Bob"         # Set only if not exists
MSET a 1 b 2 c 3         # Set multiple
MGET a b c               # Get multiple
APPEND name " Smith"     # Append to string
STRLEN name              # String length

SET visits 0
INCR visits              # 1
INCR visits              # 2
INCRBY visits 10         # 12
DECR visits              # 11
DECRBY visits 5          # 6

SET session "abc123" EX 3600    # Expires in 3600 seconds
SET token "xyz" PX 60000        # Expires in 60000 milliseconds
EXPIRE key 300                  # Set TTL on existing key
TTL key                         # Seconds remaining (-1 = no expiry, -2 = gone)
PERSIST key                     # Remove expiry

Hashes are like objects/dictionaries — perfect for storing records.

HSET user:1 name "Alice" email "alice@example.com" age 30
HGET user:1 name              # "Alice"
HGETALL user:1                # All fields and values
HMGET user:1 name email       # Multiple fields
HDEL user:1 age               # Delete a field
HEXISTS user:1 name           # 1 (true)
HKEYS user:1                  # All field names
HVALS user:1                  # All values
HINCRBY user:1 age 1          # Increment numeric field

Lists are ordered sequences — good for queues and recent items.

RPUSH queue "task1" "task2"    # Push to right (end)
LPUSH queue "task0"            # Push to left (front)
LRANGE queue 0 -1              # Get all items
LRANGE queue 0 9               # First 10 items
LPOP queue                     # Pop from left
RPOP queue                     # Pop from right
LLEN queue                     # Length
LINDEX queue 0                 # Get by index

Sets are unordered collections of unique values.

SADD tags "python" "redis" "docker"
SMEMBERS tags                  # All members
SISMEMBER tags "python"        # 1 (true)
SCARD tags                     # Count
SREM tags "docker"             # Remove
SINTER set1 set2               # Intersection
SUNION set1 set2               # Union
SDIFF set1 set2                # Difference

Sorted sets have a score for ordering — perfect for leaderboards and rankings.

ZADD leaderboard 100 "alice" 85 "bob" 92 "charlie"
ZRANGE leaderboard 0 -1 WITHSCORES    # Ascending
ZREVRANGE leaderboard 0 2 WITHSCORES  # Top 3
ZSCORE leaderboard "alice"             # 100
ZINCRBY leaderboard 5 "bob"           # Add 5 to bob's score
ZRANK leaderboard "alice"             # Rank (0-based)
ZCOUNT leaderboard 90 100             # Count in score range

KEYS user:*              # Find keys (DON'T use in production — blocks)
SCAN 0 MATCH user:* COUNT 100  # Safe iteration
TYPE mykey               # String, list, set, hash, zset
EXISTS mykey             # 1 or 0
RENAME oldkey newkey
DBSIZE                   # Total key count
FLUSHDB                  # Delete all keys in current DB

# Terminal 1: Subscribe
SUBSCRIBE notifications

# Terminal 2: Publish
PUBLISH notifications "New order received"

# Pattern subscribe
PSUBSCRIBE user:*        # Match user:login, user:logout, etc.