Syntax regarding variables

Question

I've recently been asked to modify some powershell scripts, and I've a good understanding of the concept with variables and $. But I don't quite understand what this piece of code does and works:

[string]$env = $(throw "-env is required.)

To be more precise I wonder about the single $ sign, and the throw keyword.

/Andy

Answer 1

It is being used to make the $env parameter mandatory. [env]$env = "default" will assign "default" to env if no value is provided.

throw "error" is used to throw an exception.

Therefore [string]$env = $(throw "-env is required.")

will throw an exception if no value is provided by the user.