4. Common Commands Reference

4.1 General Commands

# View all keys (use with caution in production!)
KEYS *
# Use SCAN instead of KEYS in production
SCAN 0 MATCH user:* COUNT 10

# Check key data type
TYPE user:1001

# Check if key exists
EXISTS user:1001
EXISTS user:9999

# Delete keys
DEL temp:key1 temp:key2

# Set expiration time
EXPIRE session:abc123 3600

# Check remaining TTL
TTL session:abc123

# Remove expiration
PERSIST session:abc123

# Rename key
RENAME old_key new_key

# Check database size
DBSIZE

(integer) 1
"hash"
(integer) 1
(integer) 0
(integer) 2
(integer) 1
(integer) 3542
(integer) 1
OK
(integer) 157432

4.2 String Commands

# Set and get
SET name "Redis"
GET name

# Set only if not exists (for distributed locks)
SETNX lock:1 "holder"

# Batch operations
MSET k1 "v1" k2 "v2" k3 "v3"
MGET k1 k2 k3

# Increment / Decrement
SET counter 10
INCR counter
INCRBY counter 5
DECR counter
DECRBY counter 3

# Append string
SET greeting "Hello"
APPEND greeting " World"
GET greeting

# Get string length
STRLEN greeting

"Redis"
OK
OK
1) "v1"
2) "v2"
3) "v3"
OK
(integer) 11
(integer) 16
(integer) 15
(integer) 12
6
"Hello World"
(integer) 11

4.3 List Commands

# Push to both ends
LPUSH mylist "a" "b" "c"
RPUSH mylist "d" "e"

# View list
LRANGE mylist 0 -1

# Pop from both ends
LPOP mylist
RPOP mylist

# Get by index
LINDEX mylist 0

# List length
LLEN mylist

# Blocking pop (wait 10 seconds)
BRPOP empty_list 10

(integer) 3
(integer) 5
1) "c"
2) "b"
3) "a"
4) "d"
5) "e"
"c"
"e"
"b"
(integer) 3
nil

4.4 Hash Commands

# Set fields
HSET product:1001 name "Mechanical Keyboard" price 399 stock 50

# Get field
HGET product:1001 name

# Batch get
HMGET product:1001 name price stock

# Get all fields and values
HGETALL product:1001

# Field count
HLEN product:1001

# Increment
HINCRBY product:1001 stock -1

# Delete field
HDEL product:1001 stock

(integer) 3
"Mechanical Keyboard"
1) "Mechanical Keyboard"
2) "399"
3) "50"
1) "name"
2) "Mechanical Keyboard"
3) "price"
4) "399"
5) "stock"
6) "50"
(integer) 3
(integer) 49
(integer) 1

4.5 Set Commands

# Add members
SADD fruits "apple" "banana" "cherry"
SADD fruits "apple"

# View all members
SMEMBERS fruits

# Check membership
SISMEMBER fruits "banana"
SISMEMBER fruits "grape"

# Set size
SCARD fruits

# Random member
SRANDMEMBER fruits 1

# Remove member
SREM fruits "banana"

# Set operations
SADD setA "1" "2" "3"
SADD setB "2" "3" "4"
SINTER setA setB
SUNION setA setB
SDIFF setA setB

(integer) 3
(integer) 0
1) "apple"
2) "banana"
3) "cherry"
(integer) 1
(integer) 0
(integer) 3
1) "cherry"
(integer) 1
(integer) 2
1) "2"
2) "3"
1) "1"
2) "2"
3) "3"
4) "4"
1) "1"

4.6 Sorted Set Commands

# Add members with scores
ZADD scores 85 "Alice" 92 "Bob" 78 "Charlie" 96 "Diana" 88 "Eve"

# Ascending order (score low to high)
ZRANGE scores 0 -1 WITHSCORES

# Descending order (score high to low, ideal for leaderboards)
ZREVRANGE scores 0 2 WITHSCORES

# Get score
ZSCORE scores "Bob"

# Get rank
ZREVRANK scores "Alice"

# Score range query
ZRANGEBYSCORE scores 80 95 WITHSCORES

# Count members in score range
ZCOUNT scores 80 95

# Member count
ZCARD scores

# Increase score
ZINCRBY scores 5 "Charlie"

1) "Charlie"
2) "78"
3) "Alice"
4) "85"
5) "Eve"
6) "88"
7) "Bob"
8) "92"
9) "Diana"
10) "96"
1) "Diana"
2) "96"
3) "Bob"
4) "92"
5) "Eve"
6) "88"
"92"
(integer) 3
1) "Alice"
2) "85"
3) "Eve"
4) "88"
5) "Bob"
6) "92"
(integer) 3
(integer) 5
"83"

4.7 Server Management Commands

# View server info
INFO

# View memory info
INFO memory

# View client connections
CLIENT LIST

# View slow query log
SLOWLOG GET 10

# Check key count in current database
DBSIZE

# Switch database (0-15)
SELECT 1

# Flush current database
FLUSHDB

# Flush all databases (extremely dangerous!)
FLUSHALL

# Real-time command monitor
MONITOR

# View configuration
CONFIG GET maxmemory
CONFIG SET maxmemory 4gb

# Server
redis_version:7.2.4
redis_mode:standalone
os:Linux 5.15.0-181-generic x86_64
# Memory
used_memory_human:1.45M
maxmemory_human:0B
# Clients
connected_clients:3
(integer) 157432
OK
OK
OK
OK
1) "maxmemory"
2) "0"
OK