Core commands for strings, hashes, sets, and expiry.
The Redis commands you reach for most, grouped by data type. Redis is a key–value store where the value can be a string, list, hash, set, or sorted set — picking the right type is most of using Redis well.
The expiry section matters for caching: `SET key val EX 60` writes a value that self-deletes after 60 seconds, which is the pattern behind most cache entries and short-lived tokens.
SET key value | Set a string value. |
GET key | Read a value. |
SET key value EX 60 | Set with a 60-second expiry. |
SETNX key value | Set only if the key does not exist (lock-like). |
INCR key · INCRBY key 5 | Atomically increment a counter. |
MSET k1 v1 k2 v2 | Set multiple keys at once. |
Store an object as fields under one key.
HSET key field value | Set a field on a hash. |
HGET key field | Read one field. |
HGETALL key | Read all field/value pairs. |
HDEL key field | Delete a field. |
HINCRBY key field 1 | Increment a numeric field. |
LPUSH key v · RPUSH key v | Push to the head / tail of a list. |
LRANGE key 0 -1 | Read a range (0 to -1 = all). |
LPOP key · BRPOP key 5 | Pop; BRPOP blocks up to 5s (queue). |
SADD key m · SMEMBERS key | Add to a set; list members. |
ZADD key 1 m · ZRANGE key 0 -1 | Sorted set: add with score, read ordered. |
EXPIRE key 60 · TTL key | Set expiry; check remaining seconds. |
PERSIST key | Remove an expiry (make it permanent). |
DEL key · EXISTS key | Delete a key; test existence. |
SCAN 0 MATCH prefix:* | Iterate keys safely (never use KEYS in prod). |
TYPE key | Show a key’s data type. |
redis-cli -h host -p 6379 | Connect to a Redis server. |
INFO · DBSIZE | Server stats; number of keys. |
FLUSHDB · FLUSHALL | Wipe current DB / all DBs (careful!). |
SUBSCRIBE ch · PUBLISH ch msg | Pub/sub messaging. |
MONITOR | Stream every command in real time (debug only). |
`KEYS pattern` scans the entire keyspace in one blocking call, which can stall the server on large datasets since Redis is single-threaded. Use `SCAN`, which iterates in small batches via a cursor and does not block other clients.
Set a TTL when writing — `SET key value EX 60` — or add one later with `EXPIRE key 60`. Check the remaining time with `TTL key`, and remove the expiry with `PERSIST key`. This is the mechanism behind cache entries and short-lived sessions.