F# functions to get directories all directories within a given path

getDirectories

    let rec getDirectories' (di: DirectoryInfo) = 
        seq {
            yield di
            for sd in di.GetDirectories() do 
                yield! getDirectories' sd
        }

    let getDirectories path = 
        let di = new DirectoryInfo(path)
        if not di.Exists then
            Seq.empty
        else
            getDirectories' di

Simple snippet of F# code to get the directories for a given path