Listens for messages published to channels.
SUBSCRIBE channel [channel…]
Subscribes the client to the specified channels.
Once the client enters the subscribed state it is not supposed to issue any other commands, except for additional SUBSCRIBE, SSUBSCRIBE, PSUBSCRIBE, UNSUBSCRIBE, SUNSUBSCRIBE, PUNSUBSCRIBE, PING, RESET and QUIT commands. However, if RESP3 is used (see HELLO) it is possible for a client to issue any commands while in subscribed state.
Note that RESET can be called to exit subscribed state.
For more information, see Pub/sub.
When successful, this command doesn’t return anything. Instead, for each channel, one message with the first element being the string subscribe is pushed as a confirmation that the command succeeded.
O(N) where N is the number of channels to subscribe to.
@pubsub @slow
PSUBSCRIBE, PUBLISH, PUBSUB, PUBSUB CHANNELS, PUBSUB HELP, PUBSUB NUMPAT, PUBSUB NUMSUB, PUBSUB SHARDCHANNELS, PUBSUB SHARDNUMSUB, PUNSUBSCRIBE, SPUBLISH, SSUBSCRIBE, SUNSUBSCRIBE, UNSUBSCRIBE.