.NET build output cleanup script

BuildDirCleanup.fsx

#time
open System.IO
open System.Globalization

let EnumerateDirectories path =
    Directory.EnumerateDirectories(path) |> Seq.toList

let isObjOrBinFolder (folderName:string) =
    folderName.EndsWith("obj", true, CultureInfo.InvariantCulture) || folderName.EndsWith("bin", true, CultureInfo.InvariantCulture)

let rec getFoldersToDelete path =
    match EnumerateDirectories path with
    | [] -> []
    | subfolders  ->
        let targetFolders = subfolders 
                            |> List.filter isObjOrBinFolder
        let targets = subfolders 
                            |> List.filter (isObjOrBinFolder >> not) 
                            |> List.collect getFoldersToDelete
                            |> List.append targetFolders
        targets

let deleteFoldersAndSubFolders path =
    getFoldersToDelete path
    |> List.iter (fun dir -> 
        printfn "Deleting: %s" dir
        Directory.Delete dir)

let ensureDirectoryExists directory =
    if Directory.Exists directory then 
        Some directory 
    else 
        printfn "Directory %s not found and will be skipped" directory
        None

match fsi.CommandLineArgs |> Array.skip 1 with
| [||] -> 
    deleteFoldersAndSubFolders (Directory.GetCurrentDirectory())
| directoryPaths -> 
    directoryPaths 
    |> Array.map ensureDirectoryExists
    |> Array.choose id
    |> Array.iter deleteFoldersAndSubFolders
// let path = "/Users/mallibone/Downloads/Testground/test"
let defaultPath = Directory.GetCurrentDirectory()
match fsi.CommandLineArgs |> Array.skip 1 with
| [||] -> 
    deleteFoldersAndSubFolders defaultPath
| [|"--help"|] -> 
    printfn "Usage of the BuildDirCleanup script"
    printfn ""
    printfn "dotnet fsi BuildDirCleanup.fsx [dir1 dir2 .. dirn]"
    printfn ""
    printfn "In every directory provided and it's subdirectories the bin and obj folders will be deleted."
    printfn "If no directory is given the current direcotry (%s)" defaultPath
    printfn "will be recursivley searched."
    printfn ""
| directoryPaths -> 
    directoryPaths 
    |> Array.map ensureDirectoryExists
    |> Array.choose id
    |> Array.iter deleteFoldersAndSubFolders