Smashing Redis keys with bash

When evolving a data model I often tend to change stuff, and sometimes even get rid of them all together to give me a fresh start. But flushing a Redis database is not always a good idea if you want to keep some of your keys.

Instead we try to match all the keys with the same pattern as user:123456 that we need to remove.

$ redis-cli KEYS "user:*"
1) "user:123:friends"
2) "user:234"
3) "user:345:favorites"
4) "user:234"
5) "user:345"

Sadly the KEYS command in Redis only supports glob-style patterns which makes it hard to perfectly match the pattern we want. Additionally we will use grep to filter the results with a regular expression.

$ redis-cli KEYS "user:*" | grep "user:[0-9]\+$"

Now we are on to something, finally it’s time to delete the matched keys using xargs.

$ redis-cli KEYS user:* | grep 'user:[0-9]\+$' | xargs redis-cli DEL

Caution is advised when using KEYS

The KEYS command is intended for debugging purposes and may ruin performance on large databases.

Consider KEYS as a command that should only be used in production environments with extreme care.