file_numbering.scala

import scala.io.Source

if (args.length > 0) {
  val fileLines = Source.fromFile(args(0)).getLines().toList

  val maxLengthLine = fileLines.reduceLeft((a, b) => {
    if (a.length > b.length) a else b
  }).length.toString().length

  for (line <- fileLines) {
    val spaces = " " * (maxLengthLine - line.length.toString().length)
    println(spaces + line.length + " | " + line);
  }
}
else
  Console.err.println("At least one argument is needed!")