LMOVE

LMOVE removes an element from one end of the list at source and pushes it onto one end of the list at destination, as a single atomic step. The first LEFT | RIGHT picks the end of source to pop from; the second picks the end of destination to push to. destination is created if it does not exist, and source is deleted when its last element leaves.

source and destination can be the same key. LMOVE key key LEFT RIGHT rotates the list, moving its first element to the end.

A reliable-queue pattern uses LMOVE to move a job from a pending list to a processing list, so the job is not lost if the worker crashes before it finishes. To wait for an element, use BLMOVE.

Options

Option	Effect
LEFT (first)	Pop from the head of source.
RIGHT (first)	Pop from the tail of source.
LEFT (second)	Push onto the head of destination.
RIGHT (second)	Push onto the tail of destination.

Return value

Case	RESP2	RESP3
Moved	Bulk string: the element that was moved	Same
source does not exist	Nil bulk string	Null

Errors:

• ERR syntax error if a direction is not LEFT or RIGHT.
• WRONGTYPE if source holds a value that is not a list, or destination exists and is not a list. Nothing is moved in that case.

Examples

127.0.0.1:6379> RPUSH jobs:pending j1 j2 j3
(integer) 3
127.0.0.1:6379> LMOVE jobs:pending jobs:active LEFT RIGHT
"j1"
127.0.0.1:6379> LMOVE jobs:pending jobs:pending LEFT RIGHT
"j2"
127.0.0.1:6379> LRANGE jobs:pending 0 -1
1) "j3"
2) "j2"
127.0.0.1:6379> LRANGE jobs:active 0 -1
1) "j1"

Compatibility

Same as Redis 7.4 and Valkey 8.

See also

BLMOVE, RPOPLPUSH, LPOP, RPUSH, LMPOP