LINSERT key BEFORE | AFTER pivot element
Available since: 2.2.0
Time complexity: O(N) where N is the number of elements to traverse before seeing the value pivot. This means that inserting somewhere on the left end on the list (head) can be considered O(1) and inserting somewhere on the right end (tail) is O(N).
ACL categories:
@write
@list
@slow
Inserts element in the list stored at key either before or after the reference
value pivot.
When key does not exist, it is considered an empty list and no operation is
performed.
An error is returned when key exists but does not hold a list value.
Return
Integer reply: the length of the list after the insert operation, or -1 when
the value pivot was not found.