components commands comparation

component	start	stop	client	test
hdfs	start-dfs.sh	stop-dfs.sh		jps; hadoop fs -ls .
mapred	start-mapred.sh	stop-mapred.sh		jps; hadoop jar hadoop-xx.example.jar wordcount input output
hbase	start-hbase.sh	stop-hbase.sh	hbase shell	jps; enter client mode: > list
zookeeper	zkServer.sh start	zkServer.sh stop	zkCli.sh -server host:port command args e.g. zkCli.sh  -server localhost:2181 ls /zoo 由于ensemble中都 是peer的， 所以 这里的server可以是任意一台peer.	jps; echo command | nc host port e.g.  echo  ruok  | nc localhost 2181  echo  stat   | nc localhost 2181 注意：nc是在指定server,port上进行监听 ，所以 如果使用了非本地server将失败