Microsoft - Scripting - PowerShell - Notes

$PSVersionTable.PSVersion

Stack Overflow - Determine installed PowerShell version

ThepHuck - Easy way to check if your PowerShell variable is an array or not

Using the .Add or .RemoveRange methods on an array object in PowerShell will not work.

The Array.IsFixedSize property is always true for all arrays.

Source: Microsoft MSDN - Array.IsFixedSize Property via Microsoft MSDN forum - Using the .Add method on an array

Get the Name, port, location, comment, drivername and printservername of every printer on this system and export this to a CSV:

Get-WmiObject Win32_Printer | Select-Object Name,PortName,Location,Comment,DriverName,SystemName | Export-CSV test.csv

On Windows Server 2012 RTM with a language setting other than en-US, several fields in PowerShell output are empty.

An example are the LevelDisplayName and Message fields of the Get-WinEvent cmdlet.

To work around this use the following function in your script:

function Using-Culture (
  [System.Globalization.CultureInfo]
  $culture = (throw "USAGE: Using-Culture -Culture culture -Script {...}"),
  [ScriptBlock]
  $script = (throw "USAGE: Using-Culture -Culture culture -Script {...}"))
{
    $OldCulture = [Threading.Thread]::CurrentThread.CurrentCulture
    $OldUICulture = [Threading.Thread]::CurrentThread.CurrentUICulture    
    try {        
        [Threading.Thread]::CurrentThread.CurrentCulture = $culture        
        [Threading.Thread]::CurrentThread.CurrentUICulture = $culture        
        Invoke-Command $script    
    }    
    finally {        
        [Threading.Thread]::CurrentThread.CurrentCulture = $OldCulture        
        [Threading.Thread]::CurrentThread.CurrentUICulture = $OldUICulture    
    }
}

Source: Keith Hill on stackoverflow - How to set culture in PowerShell?

And execute Get-WinEvent like so:

Using-Culture -Culture en-US -Script {Get-WinEvent -logname System -maxevents 10 -computername Server01}

Sources:
vNiklas Virtualization blog - Bug in Get-WinEvent on Windows 2012?
vNiklas Virtualization blog - Bug in Powershell v3 on regional settings in Windows 2012
stackoverflow - powershell: get-winevent has no messsage data?
Microsoft Connect - Get-WinEvent does not return the content of the Event Message in V3 CTP2

Quick and dirty way to check if today is the fourth Saturday of this month:

$dateCurrentDay = Get-Date
if ( $dateCurrentDay.DayOfWeek -eq "Saturday" ) {

	# If this Saturday is the fourth Saturday of the month...
	if ( ($dateCurrentDay.Day / 7 -gt 3) -and ($dateCurrentDay.Day / 7 -le 4) ) {

		"Do something."

	}
}

Append a line of text to a file:

$strLogFile = "C:\TEMP\script.log"
"Removing current files:" | Out-File -FilePath "$strLogFile" -Append

The same can be done with command output:

Get-Item "C:\Windows\Temp\*.tmp" | Out-File -FilePath "$strLogFile" -Append

To use a parameter

$strJobName = [string]$args[0]

Source: Stackoverflow - Pass parameter from batch file to the powershell script

Add to the beginning of the script:

[CmdletBinding()]
param(
  [Parameter(Mandatory)]
  [string]$TaskName,
 
  [Parameter()]
  [string]$Property
)

Types can be (among others):

• string
• switch
• int
• boolean

Source:

• Microsoft Docs - about_Parameter_Sets
• SS64.com - PowerShell Parameters
• SS64.com - Write an Advanced Function

Rename the local computer and restart:

Rename-Computer -NewName newcomputername -Restart

Restart the local computer:

Restart-Computer

Import-Module ADDSDeployment
Install-ADDSForest `
-CreateDnsDelegation:$false `
-DatabasePath "C:\Windows\NTDS" `
-DomainMode "Win2008" `
-DomainName "testing.local" `
-DomainNetbiosName "TESTING" `
-ForestMode "Win2008" `
-InstallDns:$true `
-LogPath "C:\Windows\NTDS" `
-NoRebootOnCompletion:$false `
-SysvolPath "C:\Windows\SYSVOL" `
-Force:$true

# Create the objReport variable
$objReport = @()
 
foreach ( $strSomething in $arrSomething ) {
 
	# Create the objTemp variable
	$objTemp = "" | Select-Object "Name","Missing Group","Group Permissions"
 
	# Fill the objTemp variable
	$objTemp."Name" = $strName
	$objTemp."Missing Group" = $strGroup
	$objTemp."Group Permissions" = $strPerms
 
	# Add the filled objTemp to objReport
	$objReport += $objTemp
 
	# Cleanup
	$objTemp = $null
 
}
 
# Display the report
$objReport
 
# Cleanup
$objReport = $null

To redirect both standard and error output from a command line tool to a text file from PowerShell, either use:

command.exe 2>&1 | Out-File C:\Logs\Logfile.txt

Or:

command.exe 2>&1 > C:\Logs\Logfile.txt

Source:Stack Overflow - Redirection of standard and error output appending to the same log-file

# Check if the PowerShell prompt was started with elevation:
# Source: http://stackoverflow.com/questions/7985755/how-to-detect-if-cmd-is-running-as-administrator-has-elevated-privileges
$objPrincipal = new-object System.Security.Principal.WindowsPrincipal([System.Security.Principal.WindowsIdentity]::GetCurrent())
if ($objPrincipal.IsInRole([System.Security.Principal.WindowsBuiltInRole]::Administrator)) {
 
	Write-Host "Please start this script in an elevated PowerShell prompt." -ForeGroundColor Red
	Exit
 
}

Source: Stack Overflow - How to detect if CMD is running as Administrator/has elevated privileges?

Get-Date -UFormat %s

Get UNIX time from 30 days ago:

Get-Date -UFormat %s (Get-Date).AddDays(-30)

Source: Microsoft Scripting - PowerTip: Use UNIX Date Formatting in PowerShell

Hex to dec:

[uint32]0x41303

Source: stack overflow - Hex to Decimal Conversion - PowerShell 5

Dec to hex:

"0x{0:X}" -f 267011

> Source: stack overflow - How to convert decimal to hexadecimal variable?

$datetime = Get-Date
$datetime.ToUniversalTime()
[TimeZoneInfo]::ConvertTimeBySystemTimeZoneId($datetime, 'W. Europe Standard Time')

To get a list of timezones:

[TimeZoneInfo]::GetSystemTimeZones() | Select-Object Id, DisplayName

Source:stack overflow - How to convert powershell UTC datetime object to EST

Print most recent error message:

$Error[0].Exception