help

help命令用于查询其它命令的用法

[quickstart.cloudera:21000] > help select;
Executes a SELECT... query, fetching all rows

直接输入help不带其它命令会列出目前可用的命令：

[quickstart.cloudera:21000] > help;

Documented commands (type help <topic>):
========================================
connect   exit     history  profile  select  shell  unset  values   with
describe  explain  insert   quit     set     show   use    version

Undocumented commands:
======================
alter  create  desc  drop  help  load  summary

version

version命令用于查看impala的当前版本。

[quickstart.cloudera:21000] > version;
Shell version: Impala Shell v2.2.0-cdh5.4.2 (b7f0e80) built on Tue May 19 16:45:28 PDT 2015
Server version: impalad version 2.2.0-cdh5.4.2 RELEASE (build b7f0e80e29971632ae1c422243d56c9ef65b8c5b)

history

列出最近执行的一些命令，作用类似于Linux下的history。

[quickstart.cloudera:21000] > history;
[1]: show tables ;
[2]: hrlp;
[3]: help;
[4]: help select;
[5]: version;
[6]: history;

quit / exit

用于从impala-shell中退出。

[quickstart.cloudera:21000] > exit;
Goodbye root

connect

用于连接到特定端口的实例，如果没有指定的话默认连接到本机的21000端口。

[quickstart.cloudera:21000] > connect;
Connected to quickstart.cloudera:21000
Server version: impalad version 2.2.0-cdh5.4.2 RELEASE (build b7f0e80e29971632ae1c422243d56c9ef65b8c5b)

.