Spark supports writing programs interactively using the Scala, Python, or R REPL (that is, the Read-Eval-Print-Loop, or interactive shell). The shell provides instant feedback as we enter code, as this code is immediately evaluated. In the Scala shell, the return result and type is also displayed after a piece of code is run.
To use the Spark shell with Scala, simply run ./bin/spark-shell from the Spark base directory. This will launch the Scala shell and initialize SparkContext, which is available to us as the Scala value, sc. With Spark 2.0, a SparkSession instance in the form of Spark variable is available in the console as well.
Your console output should look similar to the following:
$ ~/work/spark-2.0.0-bin-hadoop2.7/bin/spark-shell ...
