127.0.0.1:6379> SET k1 v1 OK 127.0.0.1:6379> GET k1 "v1" 127.0.0.1:6379> SET k1 v2 OK 127.0.0.1:6379> GET k1 "v2" 127.0.0.1:6379> SET k1 v3 NX (nil) 127.0.0.1:6379> GET k1 "v2" 127.0.0.1:6379> DEL k1 (integer) 1 127.0.0.1:6379> SET k1 v3 NX OK 127.0.0.1:6379> GET k1 "v3"