this example Scala scripts executes a regex to all files recursively. it uses apache tika UniversalEncodingDetector to filter only text files. it uses a regex to find all lines containing the word "super", except if this word is part of the larger word "superstition" or "supernatural".

ExampleScalaAck.scala

import java.io.File
import org.apache.tika.detect._
import org.apache.tika.metadata._
import org.apache.tika.mime._
import org.apache.tika.io._
import org.apache.tika.parser.txt._
import resource._

def recursiveListFiles(f: File): List[File] = {
  val these = f.listFiles.toList
  these.filter(!_.isDirectory) ++ these.filter(_.isDirectory).flatMap(recursiveListFiles)
}

def isTextFile(file: File) = managed(TikaInputStream.get(file)).map(input => {
  val mediaType = new TextDetector().detect(input, null)
  mediaType.compareTo(MediaType.TEXT_PLAIN) == 0
}).opt.get

def getEncoding(file: File): Charset = managed(TikaInputStream.get(file)).map(input => {
  new UniversalEncodingDetector().detect(input, new Metadata())
}).opt.get

def read(file: File) = {
  io.Source.fromFile(file, getEncoding(file).name)
}

def processFileLines(file: File, matches: (String) => Boolean) {
  val lines = read(file).getLines().zipWithIndex.filter {case (text, _) => matches(text)}
  if (lines.nonEmpty) {
    println(Console.YELLOW + file + ":" + Console.BLACK)
    lines.foreach{ case (text, index) =>  println(index + ": " + text)}
    println()
  }
}

val dir = "/Users/david/Downloads"
def matches(line: String) = line.matches("(?i).*(?!superstition)(?!supernatural)super.*")
val files = recursiveListFiles(new File(dir)).filter(isTextFile)
files.foreach(file => processFileLines(file, matches))


/*
sbt:
libraryDependencies += "org.apache.tika" % "tika-core" % "1.5"
libraryDependencies += "org.apache.tika" % "tika-parsers" % "1.5"
libraryDependencies += "com.jsuereth" %% "scala-arm" % "1.3"


download the list of free books from gutenberg.org
$ cd ~/Downloads
$ curl http://www.gutenberg.org/cache/epub/feeds/rdf-files.tar.bz2 | tar -jxf -
$ scala ExampleScalaAck.scala

/Users/david/Downloads/cache/epub/3328/pg3328.rdf:
89:     <dcterms:title>Man and Superman: A Comedy and a Philosophy</dcterms:title>

/Users/david/Downloads/cache/epub/36437/pg36437.rdf:
134:         <pgterms:alias>Super, Ovando Byron</pgterms:alias>
136:         <pgterms:name>Super, O. B. (Ovando Byron)</pgterms:name>

/Users/david/Downloads/cache/epub/41481/pg41481.rdf:
71:     <dcterms:title>Astounding Stories of Super-Science January 1930</dcterms:title>
*/