Just a handy tip - you don't have to cast enum types in powershell usually. It will do that for you if that's the only constructor (or method) overload that makes sense:

$accessrule = New-Object system.security.AccessControl.FileSystemAccessRule $userName, `
     "Modify",  "ContainerInherit,ObjectInherit", "None", "Allow"

So when I say "only overload that makes sense," what do I mean by that? Take this method for example which has two overloads (meaning it has two different sets of parameters you could use):

void MyMethod(string a, string b, string c)

void MyMethod(string a, enum b, string c)

If you try to call that method with $o.MyMethod("foo", "foo", "foo"), it will pick the first version that takes three strings. In that case, you would have to cast/convert the enum to its native type so that powershell will pick the right method.

With PowerShell’s new –STA startup switch, interacting with the Windows Forms object model was never so easy:

PS> $text = & {powershell –sta {add-type –a system.windows.forms; [windows.forms.clipboard]::GetText()}}

Easy, eh?

As we all [should] know, running scripts downloaded from the Internet is a risky business. But sometimes you know exactly where they came from, and you trust the source. The problem arrives when you’re on a server without any of your familiar utilities and you’ve just downloaded a zip of several ps1 scripts. Unzipping the zip via the windows built-in zip handler in explorer will preserve the Zone.Identifier information for the extracted files. This means that even if you have your Execution Policy set to RemoteSigned (which most people seem to have – it’s a sensible balance), the now “local” scripts are treated as remote and they will not run. Ideally you should “unblock” the zip file before extracting the files; all extracted files are then also “unblocked.” Unblocking a file is as simple as right-clicking it in Explorer and choosing “Properties.” (see figure 1).

Now, sometimes you don’t have this luxury. Either someone else downloaded/extracted the files or you are logged in remotely via PowerShell Remoting/WINRM for example. Thankfully, the annoyingly talented Mark Russinovich has written a great little tool for stripping NTFS ADS (alternate data streams – where the zone indentifier information is attached to a regular file) called streams.exe. He’s also made the tool easily available via a UNC path: \\live.sysinternals.com\tools\streams.exe Usage is simple: just start in the root directory of the extracted scripts and run: streams –s –d *.ps1 ; the –s means traverse subdirectories and –d instructs it to delete any alternate data streams from the files.

The CodePlex guys do it again. This is a great feature that will surely help large projects garner a bit more help and support through the use of better developer documentation for getting contributors up to speed. The only thing that’s missing is syntax highlighting support for the PowerShell language. Vote for the feature here - Wiki Syntax Highlighting for PowerShell

You’ll need a CodePlex account for this I think. More information on the July 22nd release:

Syntax highlighting has been added to project wiki pages. See the Wiki Markup Guide for details.
Also added is mailing list support for project discussions: start or respond to a discussion from your e-mail client; get notifications of new responses as they come in, or in daily digest format. Now users can subscribe to an entire project’s discussions, including all new discussions posted to the project. See Mailing Lists Documentation for more information.
Feature requests addressed in this release:
Syntax Highlighting Extension
Feature request: Mailing lists
Issues addressed in this release:
HTTPS should be dropped
HTTPS in forums causes browser warnings
Feature request: please let me input ENTER in release description textbox
Pressing enter while in textarea submits form

In the latest PowerShellCX changeset, archive read and extract support is finally available. Sorry there are no binary builds yet. Use the Extract-Archive cmdlet as a stand-alone to extract all files. Use Read-Archive to generate ArchiveEntry objects which can be piped through Where-Object for filtering and eventual consumption by Extract-Archive (which can accept ArchiveEntry as well as FileInfo pipeline input). I’ve got progress reporting working too for extract. I’ve added support for reading/extracting SevenZip, Arj, BZip2, Cab, Chm, Cpio, Deb, GZip, Iso, Lzh, Lzma, Nsis, Rar, Rpm, Tar, Wim, Z & Zip.  Yes, you did see ISO support in that list Write support is only zip, bzip2, tar and gzip still.

There are more features coming, including encrypted archive support.