PowerShell v5

Starting a PowerShell window as a Domain Admin

If you run as a limited user on your own desktop, as you should, it's useful to keep a separate PowerShell window open as the Domain Administrator. I give that window a nice dark red background so I know instantly that I'm in a powerful window and to be appropriately careful. But how can I actually start a window as a different account, and using Run As Administrator? Ah, so glad you asked.

$AdminCred = Get-Credential -UserName "TreyResearch\domainadmin" `
                            -Message "Enter your password for the DomainAdmin account:" 
Start-Process PowerShell.exe -Credential $AdminCred `
                             -ArgumentList "Start-Process PowerShell.exe -Verb RunAs" `
                             -NoNewWindow

Save this as "Start-myAdmin.ps1" or equivalent and it's always available. The nice thing about using Start-Process with the NoNewWindow parameter is that it doesn't leave a spare window open. Try it. It will make it just that much easier to run as a limited user with no administrative rights, even on your own workstation. And really, when you have the power to be a domain admin, you really, really, really shouldn't run any other way.

Param() Tricks

One of the new features of PowerShell v5 is support for creating hard links, symbolic links and junctions. This is long overdue, and much appreciated. Before, I'd been forced to the workaround of using "cmd /c mklink" to create links, and I'm always glad to find a way to get rid of any vestige of cmd. Plus, having it as a part of PowerShell gives me way more flexibility in creating scripts.

 

As I was looking at some of my existing scripts, it occurred to me that I should be taking advantage of hard links in more scripts. I already use hard links for my various RDP connects, using a long switch statement. (I'll write that up one of these days, it's actually pretty cool.) But what caught my eye today was the script I wrote to create virtual machines for my labs -- New-myVM.ps1. I have a -Client parameter to the script that is a Boolean, defaulted to $False:

[CmdletBinding()]
Param([Parameter(Mandatory = $True,Position = 0)]
      [alias("Name")]
      [string]
      $VmName,
      [Parameter(Mandatory=$False)]
      [Boolean]
      $Client=$False
      )

Which is OK, but it occurred to me that I could do better. So, first, I created a new, hard-linked file with:

New-Item -Type HardLink -Name New-myClientVM.ps1 -Path .\New-myVM.ps1

Now I have one file with two names. Cool. So, let's take that a step further. I can tell which version of it I called from the command line by taking advantage of the automatic PowerShell variable $myInvocation:

$myInvocation.mycommand.name

This returns the filename (".name") of the command (".mycommand") that was executed ($myInvocation). So now, I can use:

$client =  ($myInvocation.mycommand.name -match "client")

I put that near the top of the script, and now I could branch depending on whether I was creating a server VM or a client VM. Which was definitely better, but still left me thinking it could be improved.

 

So, how about making the whole thing a lot cleaner by getting rid of that extra line? After all, I'm creating a variable and defaulting its value to $false, but why not default its value more intelligently, controlled by which file I executed to create the VM? I can still override it with the parameter (so no scripts that call this script will break), but now, I can set it automatically without using a parameter at all.

[CmdletBinding()]
Param([Parameter(Mandatory = $True,Position = 0)]
      [alias("Name")]
      [string]
      $VmName,
      [Parameter(Mandatory=$False)]
      [Boolean]
      $Client=($myInvocation.myCommand.Name -match "Client")
      )

Now that pleases me. It feels "cleaner", it's clear what I'm doing, and it doesn't take any longer to evaluate than it would as a standalone line.

Starting PowerShell Automatically – Revisited

A few months ago, I posted a quick blog on how I set PowerShell to start automatically when I log in. Well, it occurred to me that I should extend that to show you how I set the console window parameters so that my PowerShell windows are the right size and font, since on all my systems I use the same basic settings (except for my Surface Book with the 4K addon monitor -- my old eyes need a bit bigger on that, so I adjusted the values accordingly.)

The function I use to set the console size, font and font weight is: (FontSize here translates to 18 point on my FullHD systems)

Function Set-myDefaultFont () {
   $64bit = "HKCU:\Console\%SystemRoot%_System32_WindowsPowerShell_v1.0_powershell.exe"
   $Default = "HKCU:\Console"
   Set-ItemProperty -Path $Default -Name FaceName   -Value "Consolas"
   Set-ItemProperty -Path $Default -Name FontSize   -Type DWord -Value 0x00120000
   Set-ItemProperty -Path $Default -Name FontWeight -Type DWord -Value 0x000002bc
   Set-ItemProperty -Path $Default -Name FontFamily -Type DWord -Value 0x00000036 
   Set-ItemProperty -Path $Default -Name QuickEdit  -Type DWord -Value 0x00000001
   Set-ItemProperty -Path $64bit -Name FaceName     -Value "Consolas"
   Set-ItemProperty -Path $64bit -Name FontSize     -Type DWord -Value 0x00120000
   Set-ItemProperty -Path $64bit -Name FontWeight   -Type DWord -Value 0x000002bc
   Set-ItemProperty -Path $64bit -Name FontFamily   -Type DWord -Value 0x00000036 
   Set-ItemProperty -Path $64bit -Name QuickEdit    -Type DWord -Value 0x00000001
}

That's all there is to it. I've added this function to the Set-myPowerShellStart.ps1 script, and I call that whenever I create or log onto a new system. If you prefer different sizes or a different font, simply change the values to match what you need. For example, if you want a 16 point font, try a value of 0x00100000.

ETA: Fixed value of FontSize.

Mapping Drives Revisited

In my old drive mapping post, I was forced to do some fairly ugly stuff because I had to call the old net use command. Yech. Eventually, we got New-PSDrive, and that helped, but in PowerShell v5 (Windows 10's version), we get New-SmbMapping and it actually works. (New-SmbMapping was added earlier, but there were issues. Those appear to be resolved in the final version of v5.)

 

When New-PSDrive finally had persistent drive mappings, I replaced my my old MapDrives.cmd file with a new MapDrives.ps1 that used the New-PSDrive syntax:

New-PSDrive -Name I -root \\srv2\Install -Scope Global -PSProv FileSystem -Persist

A bit awkward, but it works. However, it sometimes ran into problems with drives that were mapped with net use, so I was glad when we finally got a useful version of New-SmbMapping. Now the syntax for mapping my I: drive to \\srv1\install is:

New-SmbMapping -LocalPath I: -RemotePath \\srv2\Install -Persistent $True

Great. But it doesn't have a -Force parameter, so I can't tell it to override any maps that already exist. That requires cleaning up the old maps before I make new ones. For that, we have Remove-SmbMapping and Remove-PsDrive.

function Remove-myMaps () {
   $DriveList = (Get-SmbMapping).LocalPath
   write-verbose "Removing drives in DriveList: $drivelist"
   Foreach ($drive in $DriveList) {
      $psDrive = $drive -replace ":" #remove unwanted colon from PSDrive name
      Write-Verbose "Running Remove-SmbMapping -LocalPath $Drive -Force -UpdateProfile"
      Remove-SmbMapping -LocalPath $Drive -Force -UpdateProfile 
      If ( (Get-PSDrive -Name $psDrive) 2>$Null ) {
      Write-Verbose "Running Remove-PsDrive -Name $psDrive -Force "
      Remove-PSDrive -Name $psDrive -Force
      }
   }
      write-host " "
      $DriveList = (Get-SMBMapping).LocalPath
      Write-Verbose "The drive list is now: $DriveList"
}

As you might have noticed, PsDrives don't have a colon, and SmbMapping drives do. But PowerShell gives us the useful -replace operator, allowing us to simply remove the stray colon from the drive letter that SmbMapping has.

So, here's the entire script. Feel free to use it as the basis for your own mappings, but please, respect the copyright and don't republish it but link to here instead. Thanks. :)

Charlie.

<#
.Synopsis
Maps network drives to drive letters
.Description
Map-myDrive is used to map network resources to local drive letters. It can use SmbMapping or PsDrive to 
do the mapping, but defaults to simple PsDrives for historical reasons. (SmbMapping was buggy when it 
was first introduced!)
.Example
Map-myDrive

Performs a standard drive mapping on the local machine using New-PsDrive syntax.
.Example
Map-MyDrive -SMB

Performs a standard drive mapping on the local machine using New-SmbMapping syntax.
.Example
Map-MyDrive -SMB -Force

Performs a standard drive mapping on the local machine using New-SmbMapping syntax, and
forces an unmapping of any existing drive maps before remapping.
.Example
Map-MyDrives -SMB -Force -AtHome $False

Performs a standard drive mapping on the local machine using New-SmbMapping syntax, and
forces an unmapping of any existing drive maps before remapping. The script assumes that 
it is NOT being run in my home domain, and therefore does only local mappings.
.Parameter SMB
When set, Map-myDrive uses SMB syntax to do the drive mappings
.Parameter Force
When set, Map-myDrive completely unmaps any existing drive mappings, and then remaps them. 
.Parameter AtHome
When True, Map-myDrive assumes that it has connectivity to the home domain resources. When
False, it assumes no home domain resources are available and maps to local shares. 
.Inputs
[switch]
[switch]
[switch]
[Boolean]
.Notes
    Author: Charlie Russel
 Copyright: 2016 by Charlie Russel
          : Permission to use is granted but attribution is appreciated
   Initial: 10 June, 2012
   ModHist: 26 June, 2012 A single, cleaner, call to GWMI
          : 26 April,2015 Cleaned up smb unmapping failures, and added Verbose
          : 27 June, 2015 New unmapping function
          : 04 Sept, 2016 Added AtHome Boolean to override environment, Force switch to force unmapping/remapping
          :
#>
[CmdletBinding(SupportsShouldProcess=$True)] 
Param ([Parameter(Mandatory=$false)][Switch]$SMB,
       [Parameter(Mandatory=$false)][Switch]$Force,
       [Parameter(Mandatory=$false)][Boolean]$AtHome=$True)

#
Write-Verbose "Running mapdrives.ps1 with SMB set to $SMB"
Write-Verbose "Athome is set to $AtHome"
Write-Verbose "Force is $Force"

$Psh = Get-Process PowerShell

# Start by checking for mapped drives
$DriveList = $Null
$PSDriveList = $Null
#$DriveList = Get-WMIObject Win32_LogicalDisk | Where-Object { $_.DriveType -eq 4 }

$DriveList = (Get-SMBMapping).LocalPath
write-verbose "The DriveList is: $DriveList"

if ($DriveList) {
   $PSDriveList = $DriveList -replace ":"
   write-verbose "The PSDrivelist is: $PSDriveList"
}

# Unmap any lingering ones
Function Remove-myMaps () {
   write-verbose "Removing drives in DriveList: $drivelist"
   Foreach ($drive in $DriveList) {
      $psDrive = $drive -replace ":" #remove unwanted colon from PSDrive name
      Write-Verbose "Running Remove-SmbMapping -LocalPath $Drive -Force -UpdateProfile"
      Remove-SmbMapping -LocalPath $Drive -Force -UpdateProfile 
      If ( (Get-PSDrive -Name $psDrive) 2>$Null ) {
      Write-Verbose "Running Remove-PsDrive -Name $psDrive -Force "
      Remove-PSDrive -Name $psDrive -Force
      }
   }
      write-host " "
      $DriveList = (Get-SMBMapping).LocalPath
      Write-Verbose "The drive list is now: $DriveList"
} 

Function Map-myPSDrive () {
   New-PSDrive -Name I -root \\server\Install    -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name J -root \\server\Download   -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name S -root \\server\SharedDocs -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name W -root \\server\Working    -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name H -root \\server2\Download  -Scope Global -PSProv Filesystem -Persist
   New-PSDrive -Name K -root \\server2\Kindle    -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name M -root \\server2\Music     -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name N -root \\server2\Audible   -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name P -root \\server2\Pictures  -Scope Global -PSProv FileSystem -Persist
   New-PSDrive -Name T -root \\labserver\Captures\70-742 -Scope Global -PSProv FileSystem -Persist
}

# Map using SMBMapping. It's more robust
Function New-mySMBMaps () {
   New-SmbMapping -LocalPath I: -RemotePath \\server\Install    -Persistent $True
   New-SmbMapping -LocalPath J: -RemotePath \\server\Download   -Persistent $True
   New-SmbMapping -LocalPath S: -RemotePath \\server\SharedDocs -Persistent $True
   New-SmbMapping -LocalPath W: -RemotePath \\server\Working    -Persistent $True
   New-SmbMapping -LocalPath H: -RemotePath \\server2\Downloads -Persistent $True
   New-SmbMapping -LocalPath K: -RemotePath \\server2\Kindle    -Persistent $True
   New-SmbMapping -LocalPath M: -RemotePath \\server2\Music     -Persistent $True
   New-SmbMapping -LocalPath N: -RemotePath \\server2\Audible   -Persistent $True
   New-SmbMapping -LocalPath P: -RemotePath \\server2\Pictures  -Persistent $True
   New-SmbMapping -LocalPath T: -RemotePath \\labserver\Captures\70-742 -Persistent $True
}

Function Map-myLocal () {
   New-SmbMapping -LocalPath K: -RemotePath \\localhost\Kindle          -Persistent $False  
   New-SmbMapping -LocalPath T: -RemotePath \\localhost\Captures\70-742 -Persistent $False  
}

if(! $PSDriveList ) {
   if ($Force) { Remove-myMaps }
   Write-Verbose "SMB is set to $SMB"
   if ($SMB) { 
      If ($AtHome) { 
         New-mySMBMaps 
      } else {
         Map-myLocal
      }
   } else { 
      If ($AtHome) { 
         Map-myPSDrive 
      } else {
         Map-myLocal
      }
    }
} else { 
   # $Psh.count is the number of open PowerShell windows. I know that if it's less than or equal
   # to 2, then I haven't yet mapped the drives on both limited user and administrative windows. 
   # Therefore, we need to mapdrives here. Or, if I have run this with a -Force command, obviously.
   if (($Psh.count -le 2) -OR ($Force)) {
   Remove-myMaps
   Write-Verbose "SMB is set to $SMB"
   if ($SMB) { 
      If ($AtHome) { 
         New-mySMBMaps 
      } else {
         Map-myLocal
      }
   } else { 
      If ($AtHome) { 
         Map-myPSDrive 
      } else {
         Map-myLocal
      }
   }
  }
}

Shutting Down Running VMs – Revisited

A couple of years ago, I posted a perfectly good snippet for shutting down the running VMs on a machine. But the code there is very much the "old syntax" and not terribly elegant.  For shutting down all the running RODCs, I used:

Get-VM -Name *rodc* | Where-Object {$_.State -eq "Running" } | Foreach-Object { Stop-VM $_.Name }

Which is a nuisance to type, frankly. So, here's the PowerShell v5 version. Much slicker, much easier to remember, and a lot quicker to type.

Get-VM -Name *rodc* | Where State -eq "Running" | Stop-VM

Simpler and easier to follow. It still requires a two-pipe solution, but that's only because we only wanted to stop the running VMs without any warning messages. If we didn't care about spurious warning messages, the answer gets even simpler:

Stop-VM *rodc*

All things considered, I'm in favour of simpler. And the odd warning message doesn't concern me, so I'll go with the last solution 90% of the time. Note that this accepts a -ComputerName parameter for running against a remote computer, a -PassThru parameter for echoing out which VMs it's shutting down, and a -TurnOff parameter to just kill the VMs, rather than use an orderly shutdown.

 

Historical note:  If you want to see a really complicated way to do this, written before we had "Stop-VM" as a cmdlet, take a look at this post from 4 years ago! I'm so glad PowerShell is doing all the heavy lifting now!

 

 

Setting Console Colours

As I described in my previous post, I always open both an admin and non-admin PowerShell window when I log on to a computer. To tell the two apart, I set the background colour of the Admin window to dark red, with white text, and the non-admin window to a white background with dark blue text. The result is clearly and immediately different, warning me when I'm running as an administrator. To do that, I use the following:

$id = [System.Security.Principal.WindowsIdentity]::GetCurrent() 
$p = New-Object system.security.principal.windowsprincipal($id)

# Find out if we're running as admin (IsInRole). 
# If we are, set $Admin = $True. 
if ($p.IsInRole([System.Security.Principal.WindowsBuiltInRole]::Administrator)){ 
   $Admin = $True 
} else { 
   $Admin = $False 
}

if ($Admin) { 
      $effectivename = "Administrator" 
      $host.UI.RawUI.Backgroundcolor="DarkRed" 
      $host.UI.RawUI.Foregroundcolor="White" 
      clear-host 
   } else { 
      $effectivename = $id.name 
      $host.UI.RawUI.Backgroundcolor="White" 
      $host.UI.RawUI.Foregroundcolor="DarkBlue" 
      clear-host 
}

 

That works great for older versions of the Windows PowerShell console, but starting with PowerShell v5, that can have an unintended side effect. In PowerShell v5, we now have PSReadLine that does context sensitive colouration of the command line. But the default PowerShell console has a dark blue background, with white text. And when I changed the background colour of my non-admin PowerShell window to white, it gets a little hard to read!! So, to fix that, I use Set-PSReadLineOption to change the various kinds of context sensitive colour changes to something that works with a light background. We don't want to do that for the dark red background of the Admin window, so we'll need to check which colour we are and adjust accordingly.

First, get the current colour:

$pData = (Get-Host).PrivateData 
$curForeground = [console]::ForegroundColor 
$curBackground = [console]::BackgroundColor

You'll only want to configure the context sensitive colouring options if you're running on Windows 10 or Server 2016. Prior versions of Windows didn't have the new system console that comes with Windows 10. So you'll want to check that the build number is > 10240

$Build = (Get-WmiObject Win32_OperatingSystem).BuildNumber

If $Build -ge 10240, then set the various context sensitive tokens to work with the colour we have.

# PowerShell v5 uses PSReadLineOptions to do syntax highlighting. 
# Base the color scheme on the background color 
If ( $curBackground -eq "White" ) { 
      Set-PSReadLineOption -TokenKind None      -ForegroundColor DarkBlue  -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Comment   -ForegroundColor DarkGray  -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Keyword   -ForegroundColor DarkGreen -BackgroundColor White 
      Set-PSReadLineOption -TokenKind String    -ForegroundColor Blue      -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Operator  -ForegroundColor Black     -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Variable  -ForegroundColor DarkCyan  -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Command   -ForegroundColor DarkRed   -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Parameter -ForegroundColor DarkGray  -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Type      -ForegroundColor DarkGray  -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Number    -ForegroundColor Red       -BackgroundColor White 
      Set-PSReadLineOption -TokenKind Member    -ForegroundColor DarkBlue  -BackgroundColor White 
      $pData.ErrorForegroundColor   = "Red" 
      $pData.ErrorBackgroundColor   = "Gray" 
      $pData.WarningForegroundColor = "DarkMagenta" 
      $pData.WarningBackgroundColor = "White" 
      $pData.VerboseForegroundColor = "DarkYellow" 
      $pData.VerboseBackgroundColor = "DarkCyan" 
   } elseif ($curBackground -eq "DarkRed") { 
      Set-PSReadLineOption -TokenKind None      -ForegroundColor White    -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Comment   -ForegroundColor Gray     -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Keyword   -ForegroundColor Yellow   -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind String    -ForegroundColor Cyan     -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Operator  -ForegroundColor White    -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Variable  -ForegroundColor Green    -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Command   -ForegroundColor White    -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Parameter -ForegroundColor Gray     -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Type      -ForegroundColor Magenta  -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Number    -ForegroundColor Yellow   -BackgroundColor DarkRed 
      Set-PSReadLineOption -TokenKind Member    -ForegroundColor White    -BackgroundColor DarkRed 
      $pData.ErrorForegroundColor   = "Yellow" 
      $pData.ErrorBackgroundColor   = "DarkRed" 
      $pData.WarningForegroundColor = "Magenta" 
      $pData.WarningBackgroundColor = "DarkRed" 
      $pData.VerboseForegroundColor = "Cyan" 
      $pData.VerboseBackgroundColor = "DarkRed" 
   } 
}

Finally, let's make sure that console window is the right size, and while we're at it, set the window title. (This is a workaround for a PITA bug in recent builds of Windows 10/Server 2016 that seems to have problems setting the console window size and keeping it!)

$host.ui.rawui.WindowTitle = $effectivename + "@" + $HostName +" >" 
$Host.UI.RawUI.WindowSize = New-Object System.Management.Automation.Host.Size(120,40)

 

Now, with all of this, you have effective, context-sensitive, command-line colouring of your PowerShell windows.

 

ETA: The Console as we know it is completely broken in recent builds of Windows 10. As of August, 2018, you can't effectively set the background color of the console and have it stick, plus they completely changed the behaviour of Set-PSReadlineOption by changing the parameters, and removing support for -TokenKind with FG/BG colors to totally break this script. Sigh.