In PowerShell V2, we added a bunch of computer management cmdlets:

PS >Get-Command -Noun Computer | Format-Table -Auto

CommandType Name                Definition
-———- —-                ———-
Cmdlet      Add-Computer        Add-Computer [-DomainName] <String> [-Credent
Cmdlet      Checkpoint-Computer Checkpoint-Computer [-Description] <String> [
Cmdlet      Remove-Computer     Remove-Computer [[-Credential] <PSCredential>
Cmdlet      Restart-Computer    Restart-Computer [[-ComputerName] <String[]>]
Cmdlet      Restore-Computer    Restore-Computer [-RestorePoint] <Int32> [-Ve
Cmdlet      Stop-Computer       Stop-Computer [[-ComputerName] <String[]>] [[

Astute followers of our CTP process might notice a missing entry in this list when compared to earlier builds: the Rename-Computer cmdlet.

I don’t like to post line noise very often, but I did break that exception in the Holiday Wishes post a few weeks ago. I hate quoting entire blog posts, but, 177 characters isn’t too bad:

'(18029799997931744,139752119745773792|%{"{0,60}"-f [Convert]::ToString($_, 2).Replace("0"," ")})-split''(.{12}|Mh)''|?{$_}'|%{iex $_;-join[char[]]$_[[char[]]"nOBB7[4oBCaenRa"]}

When it runs, you get this for output:

PS >'(18029799997931744,139752119745773792|%{"{0,60}"-f [Convert]::ToString
($_, 2).Replace("0"," ")})-split''(.{12}|Mh)''|?{$_}'|%{iex $_;-join[char[]
]$_[[char[]]"nOBB7[4oBCaenRa"]}
     1
    111
   11111
  1111111
    111
   11111
 111111111
11111111111
    111
    111
Merrv ChristMas 

While it may seem like magic, it in fact was not – just some terribly obtuse PowerShell scripting. Let’s take a look at what makes it tick. Rather than deconstruct it, we’ll build it up from scratch.

'(18029799997931744,139752119745773792|%{"{0,60}"-f
[Convert]::ToString($_, 2).Replace("0"," ")})-split''(.{12}|Mh)''|?{$_}'|
%{iex $_;-join[char[]]$_[[char[]]"nOBB7[4oBCaenRa"]}

Marcel has been posting some interesting articles on using PowerShell to generate the MD5 hashes of files.  Now, an MD5 hash of a file is just an array of bytes.  Typical hashing programs display this in a more friendly manner:

PS:15 C:\Temp >md5sum 71-59-B7.bmp
a05805e638741bb767f97c0e88962952 *71-59-B7.bmp

Although the output of Marcel’s scripts could definitely be crafted to display this output, they currently output the string representation of a byte array:

PS:19 C:\Temp >get-md5 (get-childitem 71-59-B7.bmp)
160 88 5 230 56 116 27 183 103 249 124 14 136 150 41 82

One of the comments in response to Marcel’s post was that PowerShell should, by default, output byte arrays as hex.  This is a good suggestion, and we can go even further with it.  Let’s write a script to give us a full hex editor-like view of a byte array:

When you’re writing a script that depends on PowerShell Remoting, it’s often helpful to know that the remoting channel is open and will support the activities of your script.

PowerShell has a Test-WSMan command, but that only verifies that a WSMan connection is possible. There are other scenarios you could be impacted by:

• Not having permission on the remote machine
• Misconfiguration of the PowerShell endpoint
• Corrupted installation
• (etc)

As you dig deeper, you realize that the only way to really test the viability of the remoting channel is to just do something on it, and verify that you got the results you expected to. Since the implementation was so simple, we didn’t write a cmdlet for it. In retrospect, the concept is more difficult than the implementation, so we probably should have written it anyways. Here’s an example function that tests the remoting connection to a specific machine.

Over the past few years, Pumpkin carving in my family has somehow ended up focusing on two themes: Math, and Knitting.

A Sierpinski Triangle – which surprisingly only took a toothpick or two to repair isolated triangles:

Sierpinski Carpet (along with a wee bit of evil, of course:)

Not being one to cut 64 of the level-three squares by hand, a cordless drill came in extremely handy.

Mandelbrot, and Koch snowflake:

One thing you might notice if you have an iPhone connecting to an Inbox via the IMAP protocol is that messages you delete tend to stick around when viewed from other devices (such as Outlook, Outlook Web Access, etc.)

This is caused by an out-of-date view of mail management, where your Inbox handles everything. When you delete an item, some IMAP clients (such as the iPhone) mark them as deleted, but don’t actually remove the item from the server. Some clients hide these deleted items. Some show them with a line through them. Some ignore the deleted flag altogether.

[Edit: This function has been improved and added to the PowerShell Cookbook module. Get it from the PowerShell Gallery.]

Awhile back, I introduced a script that allows you interact with remote TCP ports (such as Telnet.) While useful, it worked only interactively. It would be even more useful if you were able to script a network or TCP connection. Let me introduce Send-TcpRequest.ps1 v2, which allows exactly that: First, a simple scripted HTTP session:

When playing with cryptography challenges (don’t we all?,) you end up leaning on a bunch of common tasks. For example, substituting all text in a string with a set of replacements (substitution ciphers,) XORing strings together, applying dictionary-based algorithms, investigating word frequency, and more.

PowerShell lends itself really well to these challenges, and I’ve developed a small cryptography library along the way. Here it is. Your job, as a cryptographer, is to uncover the hidden comments :) (Hint: don’t spend very long. Some problems are unbreakable.)

Adam Barr blogged bits and pieces of a PowerShell RPN calculator a few years ago: first the basics, and then some tweaks to clean it up. An RPN calculator, if you haven’t played with one before, flips the way you enter data. Rather than type “2 + 2”, you type “2 2 +”. RPN-style calculation supposedly has lots of great benefits. While I understand it and can do it, I wouldn’t say I “get it.”