UPDATE NUMBER 2:

Kevin commented about a flaw in my script wherein it would keep files open until the PowerShell process was closed - a scenario I should've tested but, in all of the excitement (ha), I missed. You won't believe what the problem was, either. I forgot parentheses on my $inStream.Close() method (it looked like $inStream.Close instead of $inStream.Close() ). The reason the trap { } script block didn't catch it is because the statement was still valid... it would just display the MethodInfo like below:

MemberType          : Method
OverloadDefinitions : {System.Void Close()}
TypeNameOfValue     : System.Management.Automation.PSMethod
Value               : System.Void Close()
Name                : Close
IsInstance          : True

The [void] statement before it prevented the output from displaying, hence me not catching the bug. The script has now been fixed (hopefully). Thanks for the catch Kevin!

UPDATE:

Ignore my script. Go download the PowerShell Community Extensions instead. It has a great Get-Hash script that does everything that my script does and more. I wish I had downloaded it sooner

Jeffrey Snover posted a suggestion on the PowerShell blog recently to post automation scripts people have written in PowerShell that they use. Well, here is a script I wrote that I also submitted for the PowerShell Scripting Contest a few weeks back. The script is quite basic and is based on other code I found, but I added a little bit to it to handle some of my own needs. It calculates file hashes based on a specified hash algorithm (i.e. SHA1, MD5, etc). I like to use it to determine if a large file I've downloaded (like an ISO from MSDN) is a good file or if it was corrupted during the download.

Here is Calc-Hash.ps1:

param (
	[string] $inFile = $(throw "Usage: Calc-Hash.ps1 file.txt [sha1|md5] "),
	[string] $hashType = "sha1"
)

function Main
{
	if ($hashType -eq "")
	{
		throw "Usage: Calc-Hash.ps1 file.txt [sha1|md5] "
	}
	
	if ($hashType -eq "sha1")
	{
		$provider = New-Object System.Security.Cryptography.SHA1CryptoServiceProvider
	}
	elseif ($hashType -eq "md5")
	{
		$provider = New-Object System.Security.Cryptography.MD5CryptoServiceProvider
	}
	else
	{
		throw "Unsupported hash type $hashType"
	}
		
	$inFileInfo = New-Object System.IO.FileInfo($inFile)
	if (-not $inFileInfo.Exists)
	{
		# If the file can't be found, try looking for it in the current directory.
		$inFileInfo = New-Object System.IO.FileInfo("$pwd\$inFile")
		if (-not $inFileInfo.Exists)
		{
			throw "Can't find $inFileInfo"
		}
	}

	$inStream = $inFileInfo.OpenRead()
	$hashBytes = $provider.ComputeHash($inStream)
	[void] $inStream.Close()
	
	trap
	{
		if ($inStream -ne $null)
		{
			[void] $inStream.Close()
		}
		break
	}
	
	foreach ($byte in $hashBytes)
	{
		Write-Host -NoNewLine $byte.ToString("X2")
	}
	
	Write-Host
}

. Main

This Christmas, my wife got me one of those awesome Logitech Harmony remotes (the Harmony 880 for those who are curious, and at a great price, too). I spent the better part of last night attempting to get it set up.

The out-of-box experience is great. The remote looks and feels excellent and the docking station for it is really cool. Of course, you should charge it prior to use. I got the thing charged and then began the installation process... on my Windows Vista box. Like so many things, it doesn't officially support Vista yet. What this means practically is that it doesn't yet support things like Aero Glass (I think because of WDDM support). It kicks the whole thing down to Aero Basic while the program runs. I also had some fun with Logitech's website because of some errors their server was having related to creating some COM objects.

At this point, it doesn't look all that good. Well, to be honest, I was feeling a little upset about the whole thing, but I WAS using the remote on an unsupported OS still and everybody has server issues once in a while. I was willing to give them the benefit of the doubt so I tried their website a few hours later. The thing worked great - even with the new security settings that Internet Explorer has. The website works by downloading a special file that the Harmony Remote Client opens so that all the settings are customized on their website and then loaded to the remote. I had a few extra security dialogs, but the thing still worked great.

Once I had the remote customized to my liking, I went into the living room to try it out.

POWER!

...

POWER!

...

POWER! POWER! TURN ON! TURN ON!

What is going on?!?

My TV came on, my receiver came on, but my satellite receiver just sat there.

For those who may have read the title of this blog post, you may have already figured out what my problem was. My satellite receiver's remote uses UHF instead of IR. My Harmony remote only uses IR (AFAIK). In other words, my remote cannot talk to my satellite receiver.

*sigh*

I am happy to report that I'm planning on investigating digital cable again anyway, because my satellite company likes new sign-ups better than existing customers. They'll give you an HD receiver without any questions if you're a new customer, but if you want to upgrade your receiver later, they want to charge you $800+ for a new receiver. Yeahhh, I think I'd rather go another route, thank you.

Hopefully, the digital cable box uses an IR signal instead of a UHF signal.

For those who may be scared away from the Harmony remotes, don't be. The thing works great with everything else. I entered in the model numbers for my receiver, TV, XBox 360, and PlayStation 2 and it talks with all of them without any problems. I'd been lazy and not using my receiver for sound before because I had to get out 2+ remotes everytime, but now, I'll be enjoying some surround sound when I play games on my 360 now.

Ahhh, JavaScript error messages.

<sarcasm>
They are the epitome of the user friendly error message. Developers love them, because they always tell you exactly where the problem is. Absolute error message perfection.
</sarcasm>

Below is an example of one of these messages that a friend sent:

Nice, eh?

You can tell EXACTLY what the problem is. That... thing... is null or not an object! And we've even got a line number, too!

NOTE: The above message was generated by a script I wrote a while back that is kicked off by the window.onerror event that fires when JavaScript exceptions are thrown. It posts to an application which then emails the developers in question.

I'll tell you what it looks like.

It looks like -1.#IND.

That's what it looks like. At least if the code is using the Double.NaN constant. I sure didn't know that before I saw it and, I can tell you, it sure freaked me out when I saw that in the immediate window in Visual Studio. I was working on speeding up another dev's code here and apparently they were using NaN to signify the difference between 0 and "not yet initialized." It works pretty well for them in that case, but as I said, if you're not expecting that, it very well may throw you off.

And PowerShell is smart enough to just say NaN instead of this -1.#IND stuff.

Along the same lines, -1.#INF is apparently how Infinity is represented.

(IND would be indefinite whereas INF is infinite... makes sense I guess.)