redis-cli

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Wat het doet

Redis keeps data in memory (port 6379) and is very fast. Apps use it for caching, sessions, queues (lists, streams) and rate limiting. Valkey is the open-source fork (Linux Foundation) with the same commands; RHEL 10 ships Valkey. redis-cli runs commands, monitors the server and measures latency.

Security: Redis must never be open to the internet. Use requirepass or ACL users, bind to private addresses, and TLS when traffic leaves the host.

Zo schrijf je het

redis-cli [-h HOST] [-p PORT] [--user U --pass P | -a PASS] [--tls] [COMMAND ...]

Belangrijkste delen

Common commands

PING: Test the connection.
SET key value [EX sec] / GET key: Write / read.
DEL / EXPIRE / TTL key: Delete / set or read expiry.
SCAN 0 MATCH pattern COUNT 100: Find keys safely (not KEYS *).
INFO [section]: Server stats (memory, clients, replication).
ACL SETUSER / ACL LIST / ACL WHOAMI: Users and rights.
CONFIG GET name: Read a setting.
SLOWLOG GET 10: Slow commands.
MONITOR: Show every command live (debug only).
DBSIZE: Number of keys.

Opties 9

Meest gebruikt

Flags

-h HOST / -p PORT: Server.
--user USER --pass PASS: ACL login (prefer REDISCLI_AUTH env var).
--tls --cacert FILE: TLS connection.
-n DB: Database number.
--scan --pattern P: List keys with SCAN.
--bigkeys / --memkeys: Find big keys.
--latency / --latency-history: Measure latency.
--stat: Live stats every second.
-r N -i SEC: Repeat a command.

Voorbeelden 10

$ als gewone gebruiker# als root (of met sudo)

1Install and test

#dnf install -y valkey
#systemctl enable --now valkey
$valkey-cli ping
PONG

2Write and read with expiry

$redis-cli SET session:42 '{"user":"hosam"}' EX 3600
$redis-cli TTL session:42
$redis-cli GET session:42

3Find keys without blocking the server

$redis-cli --scan --pattern 'session:*' | head
$redis-cli DBSIZE

4Create an app user with ACLs

$redis-cli ACL SETUSER shop on '>Ch4nge-me-2026' '~shop:*' '+@read' '+@write' '-@dangerous'
$redis-cli ACL LIST
$REDISCLI_AUTH='Ch4nge-me-2026' redis-cli --user shop GET shop:cart:42

5Check memory and big keys

$redis-cli INFO memory | grep -E "used_memory_human|maxmemory_human"
$redis-cli --bigkeys

6Measure latency
```
$redis-cli --latency-history -i 5
```
7Find slow commands
```
$redis-cli SLOWLOG GET 5
```

8Secure the config

#cat /etc/valkey/valkey.conf
bind 127.0.0.1 10.20.2.20
protected-mode yes
rename-command FLUSHALL ""
maxmemory 512mb
maxmemory-policy allkeys-lru

9Connect with TLS

$redis-cli -h cache.lab.local -p 6380 --tls --cacert /etc/pki/tls/certs/lab-ca.crt PING

10Run in Kubernetes and test

$kubectl run -it --rm rcli --image=docker.io/valkey/valkey:8 -- valkey-cli -h valkey.shop.svc PING

Let op

KEYS * and FLUSHALL on production can block or wipe the server; use SCAN and rename dangerous commands.
An open Redis lets attackers write files and get a shell on the host — bind to private IPs and set a password.
Set maxmemory and a policy, or Redis uses all RAM.

Bestanden

/etc/redis/redis.conf or /etc/valkey/valkey.conf: Server config.
/var/lib/redis/: dump.rdb / appendonly files.

Tips om te onthouden

Use Redis as a cache that can be lost; for data that must not be lost, turn on AOF and backups.

Exitcodes

`0`	Success.
`1`	Error (connection, auth).

`redis-cli`

Wat het doet

Zo schrijf je het

Belangrijkste delen

Common commands

Opties 9

Flags

Voorbeelden 10

1Install and test

2Write and read with expiry

3Find keys without blocking the server

4Create an app user with ACLs

5Check memory and big keys

6Measure latency

7Find slow commands

8Secure the config

9Connect with TLS

10Run in Kubernetes and test

Let op

Bestanden

Tips om te onthouden

Exitcodes

Volledige handleiding

Wat het doet

Zo schrijf je het

Belangrijkste delen

Common commands

Opties 9

Flags

Voorbeelden 10

1Install and test

2Write and read with expiry

3Find keys without blocking the server

4Create an app user with ACLs

5Check memory and big keys

6Measure latency

7Find slow commands

8Secure the config

9Connect with TLS

10Run in Kubernetes and test

Let op

Bestanden

Tips om te onthouden

Exitcodes

Verwante commando's

Gebruikt in deze lessen

Volledige handleiding

`redis-cli`