get md5sum from path with scala

fileToMd5.scala

//inspired by http://www.michaelpollmeier.com/2018/12/10/checksum-files-scala

import java.io.File
import java.nio.file.Files
import java.security.{DigestInputStream, MessageDigest}
import scala.collection.JavaConverters._

def md5(roots: File*): String = {
  val md = MessageDigest.getInstance("MD5")
  roots.foreach { root =>
    Files.walk(root.toPath).iterator().asScala.filter( x => ! x.toFile.isDirectory).foreach { path =>
      val dis = new DigestInputStream(Files.newInputStream(path), md)
      // fully consume the inputstream
      while (dis.available > 0) {
        dis.read
      }
      dis.close
    }
  }
  md.digest.map(b => String.format("%02x", Byte.box(b))).mkString
}

// usage:
//md5(new File("somepath"))

// testing
import java.io._
import sys.process._
val pw = new PrintWriter(new File("hello.txt" ))
pw.write("Hello, world")
pw.close

"md5sum hello.txt".!!.takeWhile( _ != ' ' ) == md5(new File("hello.txt"))