Getting Started

object HelloWorld {
  def main(args: Array[String]): Unit = {
    println("Hello, world!")
  }
}

1 scala shell

scala>:q

The shortcut :q stands for the internal shell command :quit used to exit the interpreter.

2 Compile it!

The scalac command compiles one (or more) Scala source file(s) and generates Java bytecode which can be executed on any [standard JVM](http://java.sun.com/docs/books/jvms/)

scalac HelloWorld.scala

By default scalac generates the class files into the current working directory. You may specify a different output directory using the -d option.

> scalac -d classes HelloWorld.scala

3 Execute it!

The scala command executes the generated bytecode with the appropriate options:

> scala HelloWorld

scala allows us to specify command options, such as the -classpath (alias -cp) option:

> scala -cp classes HelloWorld

4 Script it!

We may also run our example as a shell script or batch command (see the examples in the man pages of the scala command).

The bash shell script script.sh containing the following Scala code (and shell preamble):

#!/usr/bin/env scala
object HelloWorld extends App {
  println("Hello, world!")
}
HelloWorld.main(args)

can be run directly from the command shell:

> ./script.sh