redis-cli is the command-line interface for Redis — used to connect to a Redis server and run commands interactively. It's essential for development, debugging, inspecting data, and administration.
redis-cli # connect to localhost:6379 (default)
redis-cli -h host -p 6379 # connect to a specific host/port
redis-cli -a password # with authentication
redis-cli -n 2 # select database number 2
# once connected, run any Redis command
127.0.0.1:6379> SET name "Ann"
127.0.0.1:6379> GET name
127.0.0.1:6379> TYPE name # the data type of a key
127.0.0.1:6379> TTL name # remaining TTL
127.0.0.1:6379> SCAN 0 MATCH user:* # safely iterate keys (NOT KEYS in prod)
127.0.0.1:6379> DBSIZE # number of keys in the DB
You run the same Redis commands you'd use from code, plus inspection commands (TYPE, TTL, SCAN, DBSIZE) to explore the data.
127.0.0.1:6379> INFO # server stats (memory, clients, stats, etc.)
127.0.0.1:6379> INFO memory # memory usage details
127.0.0.1:6379> MONITOR # ⚠️ LIVE stream of ALL commands (debug only — adds load)
127.0.0.1:6379> SLOWLOG GET # recent slow commands (performance debugging)
127.0.0.1:6379> CLIENT LIST # connected clients
INFO shows server statistics (memory, clients, hit rates); MONITOR streams all commands live (useful for debugging but adds load — use carefully); SLOWLOG finds slow commands.
redis-cli PING # => PONG (health check)
redis-cli GET name # run a single command and exit
redis-cli FLUSHDB # ⚠️ delete ALL keys in the current DB (careful!)
redis-cli --scan --pattern 'user:*' # scan keys matching a pattern
redis-cli is the essential, everyday tool for working directly with Redis, so knowing its essentials is practical, fundamental knowledge for anyone using Redis.
Developers and administrators use it constantly to connect, run commands, inspect data, and debug — it's the universal, always-available interface to a Redis server.
Knowing how to connect (to local or remote servers, with auth and database selection), run commands and inspect data (GET/SET, plus TYPE, TTL, SCAN, DBSIZE to explore what's stored), and access server info and monitoring (INFO for memory/clients/stats and crucially cache hit rates, MONITOR for live command streams in debugging, SLOWLOG for finding slow commands) is everyday practical knowledge for development, debugging, and administration.
Useful one-liners (PING for health checks, single-command execution, --scan for pattern matching) make redis-cli handy for scripts and quick checks.
Knowing the important cautions — avoiding KEYS/MONITOR excessively in production (they add load) and the danger of FLUSHDB/FLUSHALL (deleting all data) — reflects safe practical usage.
Since redis-cli is the standard, ubiquitous way to interact with Redis directly (for exploration, debugging, monitoring, and administration), and since understanding its essential commands makes working with Redis efficient, understanding redis-cli is valuable, frequently-applied knowledge — a basic competency for anyone working with Redis, analogous to knowing psql for PostgreSQL or mongosh for MongoDB, and the practical entry point for inspecting and debugging Redis.