In Redis, we use KEYS to retrieve specific keys we've defined in our database. For example, if we'd created a Redis key like this:

set someKeyName someValue

Then we could get that value by using KEYS like this:

KEYS someKeyName

Interestingly, Redis KEYS support glob style patterns - so we can match many keys using text familiar to you if you've ever worked with regex. Here are some examples:

• someK?y - the question mark represents any one character - so someKqy, someKay, someKyy, etc, are all valid.
• someK*y - the asterisk represents any character including spaces - so someKy is valid
• someK[a-d]y - to match someKay, someKby, someKcy or someKdy.
• someK[ea]y, - to match someKey or someKay
• someK[^10]y - where [^10] means any number before 10 not including 10.
• someK[^e]y - where [^e] means any letter before e, but not including e.

This glob style pattern support also lets us retrieve all keys at once. Since the asterisk (*) or wild card symbol is supported, to retrieve all keys in redis at once, you only have to run KEYS *:

KEYS *

If you have a lot of keys, this may not be what you want to do - but for certain use cases, it can be quite useful to retrieve all keys in Redis at once.