zkCli doesn't output command

nelson@nelson-laptop (0) $ ./zookeeper-3.3.6/bin/zkCli.sh -server 127.0.0.1:2181 ls /
Connecting to 127.0.0.1:2181
.... LOGS ....
2014-08-04 16:22:53,032 - INFO  [main:Environment@97] - Client environment:user.name=nelson
2014-08-04 16:22:53,032 - INFO  [main:Environment@97] - Client environment:user.home=/home/nelson
2014-08-04 16:22:53,033 - INFO  [main:Environment@97] - Client environment:user.dir=/home/nelson/git/
2014-08-04 16:22:53,035 - INFO  [main:ZooKeeper@379] - Initiating client connection, connectString=127.0.0.1:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@75af8109
2014-08-04 16:22:53,056 - INFO  [main-SendThread():ClientCnxn$SendThread@1058] - Opening socket connection to server /127.0.0.1:2181
2014-08-04 16:22:53,158 - INFO  [main-SendThread(127.0.0.1:2181):ClientCnxn$SendThread@947] - Socket connection established to127.0.0.1:2181, initiating session
2014-08-04 16:22:53,216 - INFO  [main-SendThread(127.0.0.1:2181):ClientCnxn$SendThread@736] - Session establishment complete on server 127.0.0.1:2181, sessionid = 0x147a10f7d02005a, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null
[kafka, zookeeper, mesos, marathon, chronos]
nelson@nelson-laptop (0) $ 

nelson@nelson-laptop (0) $ ./zookeeper-3.4.6/bin/zkCli.sh -server 127.0.0.1:2181 ls /
Connecting to 127.0.0.1:2181
.... LOGS ....
2014-08-04 16:22:56,480 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=nelson
2014-08-04 16:22:56,480 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=/home/nelson
2014-08-04 16:22:56,480 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=/home/nelson/git/
2014-08-04 16:22:56,481 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=127.0.0.1:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@87d53d8

nelson@nelson-laptop (0) $