Scala sys.env for undefined environment variables

Question

This expression

sys.env("HOME")

delivers the path to a home folder; in general sys.env("EnvVar") delivers the value associated to $EnvVar. However, for an environment variable $LIB not declared

java.util.NoSuchElementException: key not found: LIB

How to find out whether the variable is declared without having to catch an exception ?

Answer 1

sys.env is a Map, so you can call its get method, which returns an Option:

scala> sys.env.get("FOO")
res0: Option[String] = None

Answer 2

You can try this:

  val value = sys.env.get("EnvVar")

  println(value.getOrElse("Your default value"))