Redis cheatsheet

redis-cli — connect

Command	Description
`redis-cli -h localhost -p 6379`	Connect to server
`redis-cli -a password`	Connect with password (avoid on shared hosts)
`redis-cli -u redis://user:pass@host:6379/0`	URL-style connection
`redis-cli PING`	Health check (returns PONG)
`redis-cli --latency`	Sample round-trip latency

Service and health

Command	Description
`systemctl status redis-server`	Service status (Debian/Ubuntu)
`systemctl status redis`	Service status (RHEL)
`ss -tlnp \| grep 6379`	Confirm listener
`redis-cli INFO server`	Version, uptime, config path
`redis-cli INFO memory`	Used memory, peak, fragmentation
`redis-cli INFO stats`	Ops/sec, connections, evictions

Key commands

Command	Description
`SET key value EX 3600`	Set with 1-hour TTL
`GET key`	Read string value
`TTL key`	Seconds until expiry (-1 no TTL, -2 missing)
`TYPE key`	Data structure type
`DEL key [key ...]`	Delete keys
`SCAN 0 MATCH prefix:* COUNT 100`	Iterate keys safely
`DBSIZE`	Key count in current database

Memory and config

Command	Description
`CONFIG GET maxmemory`	Memory limit
`CONFIG GET maxmemory-policy`	Eviction policy
`MEMORY USAGE key`	Bytes used by a key
`INFO keyspace`	Keys per database

Persistence

Command	Description
`BGSAVE`	Background RDB snapshot
`LASTSAVE`	Unix time of last successful save
`INFO persistence`	RDB/AOF status, last save errors
`CONFIG GET save`	RDB auto-save rules
`CONFIG GET appendonly`	AOF enabled?

Replication

Command	Description
`INFO replication`	Role, connected replicas, lag offsets
`ROLE`	Role and replication offsets
`REPLICAOF host port`	Configure as replica at runtime
`REPLICAOF NO ONE`	Promote replica to primary

Backup and restore

Command	Description
`BGSAVE`	Trigger RDB; copy `dir`/dump.rdb when done
`cp /var/lib/redis/dump.rdb /backup/`	Copy snapshot (after BGSAVE)
`redis-cli --rdb /backup/dump.rdb`	Remote RDB download via redis-cli
`redis-server /path/redis.conf`	Start with empty dir + RDB file to restore

Debugging

# Slow commands (last 10)
SLOWLOG GET 10

# Clients and what they're doing
CLIENT LIST

# Kill a stuck client
CLIENT KILL ip:port

# Live command stream (use briefly in prod!)
MONITOR

Pro tips

Never run KEYS * on production — use SCAN
Set maxmemory and a policy before Redis eats all RAM
FLUSHALL and FLUSHDB are destructive — disable or restrict via ACL
After redis.conf changes: systemctl restart redis-server or CONFIG REWRITE for runtime-tunable params
Replication ≠ backup — schedule RDB copies; test restores

Practice scenarios

Hands-on Redis scenarios on live Linux VMs: redis