Scala one-liner for upcasing lines of text

The following is a Scala script that up-cases each line of an UTF8 encoded input file (args(0)) and prints the result to standard output:

import scala.io.Source

Console.setOut(new java.io.PrintStream(Console.out,true,"UTF8"))

Source.fromFile(args(0), "UTF8").getLines.foreach(line => print(line.toUpperCase))

If you're trusting the default character encoding to work for you, you may reduce it to:

import scala.io.Source

Source.fromFile(args(0)).getLines.foreach(line => print(line.toUpperCase))

Another way to do it, is to read the lines into an iterator, using the iterator's .map method to upcase each line:

import scala.io.Source

val lines = Source.fromFile(args(0)).getLines.map(_.toUpperCase)

lines.foreach(print)

A Java programmer may be relieved (or horrified) to learn that Scala does not have any checked exceptions. There are only runtime exceptions, and you don't need to add any try/catch statements if you don't want to.

When you run a Scala script, you can instruct the Scala interpreter to compile the script, and use the compiled version (a jar file) if it's younger than the source-file. This gives better performance (shorter start-up, etc). You use the savecompiled command line argument.