Database cheatsheet

Redis 8 Cheatsheet

redis-cli and core commands for keys, data structures and server administration.

Connecting

Open the CLI — Connect to a local server on the default port.
Connect to a remote server — Connect with a user, prompting for the password so it stays out of shell history.
Test the connection — Check that the server is reachable. It replies PONG.
Switch database — Select numbered database 1.
Show server information — Show version, uptime and other details. Use sections such as INFO memory.

Set a value — Store a string value under a key, replacing any existing value.
Get a value — Read a string value. Returns nil if the key does not exist.
Set a value that expires — Store a value that is deleted after 3600 seconds.
Set only if the key does not exist — Useful as a simple lock. Returns nil if the key exists.
Delete a key — Remove a key and its value. Returns the number of keys deleted.
Check if a key exists — Returns 1 if the key exists, 0 if not.
Check time to live — Seconds until expiry, -1 for no expiry, -2 if the key does not exist.
Set an expiry — Make an existing key expire after 60 seconds.
Increment a counter — Atomically add 1 to a numeric value, creating it at 0 if missing.
Find keys by pattern — Iterate over keys without blocking the server.
Check a key's type — Show whether a key holds a string, list, hash and so on.

Set hash fields — Store several fields on one key.
Get all hash fields — Return every field and value.
Add to a list — Push an item onto the head of a list.
Take from a list — Pop an item from the tail, which gives first-in first-out with LPUSH.
Read a list — Return every item in the list. 0 -1 means from the first item to the last.
Add to a set — Add members to a set. Duplicates are ignored.
List a set's members — Return every member of a set, in no particular order.
Add to a sorted set — Add a member with a score.
Read the top of a sorted set — Return the 10 highest scores, highest first.

Count keys — Number of keys in the current database.
Check memory use — Show memory statistics such as used_memory and the maxmemory limit.
Check one key's size — Show how many bytes a key and its value use.
See slow commands — Show the 10 most recent slow commands.
List connected clients — Show each connection and what it last ran.
Read a setting — Show the current maxmemory setting.
Save a snapshot — Write the dataset to disk in the background.
Delete every key in the database — Remove all keys from the current database.
Watch every command — Stream all commands the server receives.

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