redis-cli – Coding skill for AI agents

redis-cli — Redis Command Line Interface

When to Use

Use this skill when you need redis command-line interface (redis-cli) reference and usage guide. Use this skill whenever the user mentions redis-cli, Redis CLI, or any task involving querying, inspecting, debugging, or managing Redis from the command line. Use it for scoped key/value operations, keyspace inspection and Redis administration.

redis-cli is the primary command-line tool for interacting with Redis. It supports two modes: command-line execution (run a command and exit) and interactive mode (a REPL with tab completion, history, and hints). It also provides special modes for monitoring, latency analysis, key space scanning, and data import/export.

Official resources: [Redis CLI Docs](https://redis.io/docs/latest/develop/tools/cli/) | [Commands](https://redis.io/commands/) | [Download](https://redis.io/downloads/)

Prerequisites

# Check if redis-cli is installed
redis-cli --version

# Install options:

# macOS (Homebrew)
brew install redis

# Ubuntu / Debian
sudo apt install redis-tools

# CentOS / RHEL
sudo yum install redis

# Alpine
apk add redis

# Build from source (binary only)
make redis-cli
# Binary at: src/redis-cli

# Docker (no installation needed)
docker run -it --rm redis redis-cli -h <host> -p <port> PING

Security Considerations

> IMPORTANT: Redis provides powerful operations that can irreversibly modify or delete data.

> Pay close attention to the following safety guidelines:

• Never pass passwords via -a in production — visible in shell history and process listings. Use REDISCLI_AUTH environment variable instead.
• **KEYS * blocks the server** on large databases — always use SCAN in production code.
• MONITOR logs all commands including sensitive data — use cautiously, and never for extended periods on production servers.
• FLUSHALL / FLUSHDB are irreversible — verify target database with CLIENT LIST or INFO keyspace first.
• --rdb produces a point-in-time snapshot, not a continuous backup. Concurrent writes after the snapshot are absent; check exit status and test restore compatibility.

Quick Reference

Connection

# Basic connection (default: 127.0.0.1:6379)
redis-cli
redis-cli -h redis15.localnet.org -p 6390 PING

# With password (prefer REDISCLI_AUTH env var for security)
redis-cli --askpass PING

# URI connection
redis-cli --user username --askpass -h redis.example.com PING

# TLS
redis-cli --tls --cacert /path/to/ca.crt -h redis.example.com PING

# Specific database
redis-cli -n 2 DBSIZE

# IPv4/IPv6 preference
redis-cli -4 PING   # prefer IPv4
redis-cli -6 PING   # prefer IPv6

Command-Line vs Interactive Mode

# Command-line mode: execute one command and exit
redis-cli INCR mycounter
redis-cli GET mykey

# Interactive mode: type commands at the prompt
redis-cli
127.0.0.1:6379> PING
PONG
127.0.0.1:6379> SELECT 2
OK
127.0.0.1:6379[2]> DBSIZE
(integer) 1

The prompt shows host:port[db]. Use CONNECT <host> <port> to switch instances interactively.

Data Query Cheat Sheet

String operations (complexity depends on the command and bytes processed):

GET key                        # Get value
SET key value [NX|XX] [EX sec|PX ms|KEEPTTL]  # Set with conditions/TTL
SET key value GET              # Set new, return old value
GETSET key newvalue            # [Use SET key value GET instead]
MGET key1 key2 ...             # Get multiple values
INCR key                       # Increment integer (+1)
INCRBY key 10                  # Increment by amount
STRLEN key                     # String length
GETRANGE key 0 50              # Substring

Hash operations:

HGET key field                 # Get field value            O(1)
HMGET key f1 f2                # Get multiple fields        O(N)
HGETALL key                    # Get all fields/values      O(N)
HKEYS key                      # Get all field names        O(N)
HLEN key                       # Number of fields           O(1)
HEXISTS key field              # Check field exists         O(1)
HSCAN key 0 [MATCH pat]        # Iterate hash fields        O(1) per call

List operations:

LRANGE key 0 -1                # Get all elements           O(N)
LLEN key                       # List length                O(1)
LINDEX key 0                   # Get by index               O(N)
LPOS key value                 # Find element position      O(N)

Set operations:

SMEMBERS key                   # Get all members            O(N)
SCARD key                      # Set cardinality            O(1)
SISMEMBER key member           # Check membership           O(1)
SMISMEMBER key m1 m2           # Multi-membership check     O(N)
SSCAN key 0 [MATCH pat]        # Iterate set members        O(1) per call

Sorted Set operations:

ZRANGE key 0 -1 [WITHSCORES]           # By index              O(log(N)+M)
ZRANGE key -inf +inf BYSCORE           # By score range        O(log(N)+M)
ZRANGE key [a [z BYLEX                 # By lexicographic      O(log(N)+M)
ZCARD key                               # Member count          O(1)
ZSCORE key member                       # Get score             O(1)
ZRANK key member                        # Get rank              O(log(N))
ZSCAN key 0 [MATCH pat]                 # Iterate members       O(1) per call

Key inspection:

EXISTS key [key ...]           # Check existence (O(N) for multi) — returns count
TYPE key                       # Data type: string|list|set|zset|hash|stream  O(1)
TTL key                        # Seconds until expiry (-1=none, -2=not exists)  O(1)
PTTL key                       # Milliseconds until expiry                      O(1)
MEMORY USAGE key [SAMPLES n]   # Memory consumption in bytes                    O(N)
OBJECT ENCODING key            # Internal encoding (ziplist, hashtable, etc.)   O(1)
OBJECT IDLETIME key            # Seconds since last access                      O(1)
DBSIZE                         # Total keys in current database                 O(1)
RANDOMKEY                      # Return a random key                            O(1)

Incremental Key Scanning

SCAN divides work into smaller calls but each call still uses server CPU; tune COUNT and throttle, unlike KEYS * which should be avoided in production.

# redis-cli built-in scan mode
redis-cli --scan                          # List all keys
redis-cli --scan --pattern 'user:*'       # Filter by pattern
redis-cli --scan --pattern '*:12345*'     # Glob patterns
redis-cli --scan --count 100              # Batch size hint

# Programmatic SCAN in interactive mode
SCAN 0 MATCH user:* COUNT 100
# Returns: 1) next_cursor  2) [keys...]
# Continue with: SCAN <next_cursor> MATCH user:* COUNT 100
# Iteration complete when cursor returns 0

# Count keys matching a pattern
redis-cli --scan --pattern 'session:*' | wc -l

SCAN guarantees: a full iteration (cursor 0 → cursor 0) always returns all elements that existed for the entire duration. Elements may appear multiple times — handle duplicates in your application.

Server Inspection

# Real-time stats (updates every second, use -i to change interval)
redis-cli --stat

# Server information
redis-cli INFO server             # Server details
redis-cli INFO memory             # Memory usage
redis-cli INFO keyspace           # Database key counts
redis-cli INFO replication        # Replication status
redis-cli INFO all                # Everything

# Key space analysis
redis-cli --bigkeys               # Find largest keys by element count
redis-cli --memkeys               # Find largest keys by memory usage
redis-cli --keystats              # Combined bigkeys + memkeys with distribution

# Latency analysis
redis-cli --latency               # Continuous latency sampling
redis-cli --latency-history       # Latency over time (15s windows)
redis-cli --latency-dist          # Latency spectrum visualization
redis-cli --intrinsic-latency 5   # System baseline latency (run on Redis host)

Output Control

# Raw output (no type prefixes) — default when piping
redis-cli --raw GET mykey
redis-cli GET mykey > /tmp/output.txt    # auto raw mode

# Human-readable (force) when piping
redis-cli --no-raw GET mykey | cat

# CSV output
redis-cli --csv LRANGE mylist 0 -1

# JSON output (RESP3, use -2 for RESP2)
redis-cli --json HGETALL user:1

# Read last argument from stdin
cat /etc/services | redis-cli -x SET net_services

# Pipe commands from file
cat /tmp/commands.txt | redis-cli

Repeat Commands

# Run command N times
redis-cli -r 5 INCR counter

# Run with delay (seconds, supports decimals)
redis-cli -r -1 -i 1 INFO | grep rss_human    # infinite, every 1s

# Interactive: prefix with count
5 INCR mycounter    # runs 5 times

Server Administration

# ACL management
redis-cli ACL LIST                                    # List all users

… (full content is in the download package)