private void printVersion() {
    String version = String.format("Shell version %s, Executor is %s, version %s",
        this.getClass().getPackage().getImplementationVersion(),
        executor.getClass().getName(),
        executor.getVersion());
    writer.println(version);
  }
Handles the given command
@param command input {@link CliCommand} to handle
@return false if command is to quit, or fatal error happened that Shell should not continue running. True o.w.
@throws CommandHandlerException if unrecoverable error happened while handling the input {@link CliCommand}
samza-sql-shell/src/main/java/org/apache/samza/sql/client/impl/CliCommandHandler.java