Just type make
JAVA_OPTS="-Xmx4G" scala -nc nstream 10 $((1024*1024*64))
Note that the environmental variable JAVA_OPTS sets the maximum memory
used by Java to 4G, which is probably acceptable for most use cases.
The default is quite low and will not allow you to run nstream with
more than ~16MW.
If you're interested in running in a script mode, simple specify the file name of the source code.
JAVA_OPTS="-Xmx4G" scala -nc nstream.scala 10 $((1024*1024*64))