Available since: 2.2.0
Time complexity: O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments.
Inserts specified values at the head of the list stored at
key, only if
already exists and holds a list.
In contrary to
LPUSH, no operation will be performed when
key does not yet
Integer reply: the length of the list after the push operation.