Decrements the number stored at key by decrement.
If the key does not exist, it is set to 0 before performing the operation. An
error is returned if the key contains a value of the wrong type or contains a
string that is not representable as integer. This operation is limited to 64
bit signed integers.
See INCR for extra information on increment/decrement operations.
Return value
Integer reply: the value of key after the decrement
Examples
redis>
SET mykey "10"
OKredis> DECRBY mykey 5
(integer) 5