Streams

Various ways to slurp a file without loading its contents into memory:

val bytes  : Iterator[Byte]            = file.bytes()
val chars  : Iterator[Char]            = file.chars()
val lines  : Iterator[String]          = file.lineIterator()     //file.lines loads all lines in memory

Note: The above APIs can be traversed at most once e.g. file.bytes is a Iterator[Byte] which only allows TraversableOnce. To traverse it multiple times without creating a new iterator instance, convert it into some other collection e.g. file.bytes.toStream

You can write an Iterator[Byte] or an Iterator[String] back to a file:

file.writeBytes(bytes)
file.printLines(lines)

tee multiple outputstreams:

val s3 = s1 tee s2
s3.printWriter.println(s"Hello world") // gets written to both s1 and s2