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SET: Use “SET” command to display the name and value of all environment variables that impacts the behavior of the shell and the "SqlExecutor". Use “SET <<name>=<value>>” to set a variable.  These environment variables can also be set in the configuration file, namely namely "conf/shell-defaults.conf". 

Use "CLEAR" command to clear the screen.   
Use "EXIT" or "QUIT" to quit the shell.

Accessing Samza

Configuration

The configuration file is located at "conf/shell-defaults.conf".  Most of the variables set here can also be set in the shell via command "SET". Some of the important configurations are listed below.

shell.executor

Specifies which SQL executor to use. By default org.apache.samza.sql.client.impl.SamzaExecutor is used, a.k.a Samza SQL.

shell.debug

Some of the samza code, though not supposed to, actually prints something to the stdout and stderr when a SQL is being executed. Those messages shall not be seen by the end user, and more importantly, they mess up the terminal display. Imagine you are painting a table on the screen and refreshing it every second, and part of it are replaced by some INFO or WARNING information!

When the shell starts up it takes control of the terminal completely and turns off all output to Java System.out and System.err. To prevent the shell from doing so, set "shell.debug" to true.

Public Interfaces

Implementation and Test Plan

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