PowerShell

Here I present a PowerShell script which I find useful.
Of course, PowerShell is a Microsoft Windows based object orientated script / programming language. It has its own command line interface.
Normally I would prefer a platform independent language like Python. But within a Windows environment you can do almost anything with PowerShell. And sometimes I just do not like to perform all tasks with Excel / VBA. PowerShell can perform tasks in background mode, at a scheduled time, etc.
A first useful function is in my opinion Write-Log. It offers logging functionality.
Please read my Disclaimer​
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<#
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.SYNOPSIS
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    Write-Log -Message [string] -Severity EVER|INFO|WARN|FATAL
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.DESCRIPTION
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    This script/function enables logging within PowerShell scripts.
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​
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    Global variables which control features of this script are:
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    [string]$global:LogFilePath    - The text file into which all messages are getting written
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    [string]$global:SubName        - The name of the script calling this Log script
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    [int]$global:LogLevel          - The log levels:
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					                				   1 logs everything,
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                									   2 omits INFOs,
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                                     3 omits INFOs and WARNings,
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                									   4 only logs severity EVER messages
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    [bool]$global:WriteToHost      - $FALSE = Only write into logfile; $TRUE = Also write to Host
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.OUTPUTS
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	Write-Log writes into a logfile with name [string]$global:LogFilePath.
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	if the user has not given this, the standard filename "$PSScriptRoot\Logs\LogFile.txt" is used.
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    The contents of a log file will look like:
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    INFO: BERND-PC\Bernd 2020-02-16 12:19:36 [zip_and_copy.ps1] - Log started
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    INFO: BERND-PC\Bernd 2020-02-16 12:19:36 [zip_and_copy.ps1] - Log finished
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	In case the user has set [bool]$global:WriteToHost to $TRUE, WRite-Log also repeats all log
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	messages on screen (Host).
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​
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.PARAMETER Message
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    The message you want to log.
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​
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.PARAMETER Severity
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    The severity of the message. This can be 'INFO', 'WARN', 'FATAL', or 'EVER'.
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    If global variable LogLevel is 1 then messages with all severities will be logged.
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    If LogLevel is 2 then INFO messages will not be logged.
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    If LogLevel is 3 then INFO and WARN messages will not be logged.
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    If LogLevel is 4 then INFO, WARN and FATAL messages will not be logged.
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​
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.EXAMPLE
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    # Initialize global logging variables and make log script known
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    $global:SubName = $MyInvocation.MyCommand.Name
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    $global:LogLevel = 1
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    $global:LogFilePath = "$PSScriptRoot\Logs\LogFile_" + $SubName + "_" +
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        (Get-Date -UFormat "%Y%m%d") + ".txt"
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    $global:WriteToHost = $TRUE
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    . "$PSScriptRoot\Write-Log.ps1"
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​
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.EXAMPLE
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    # How to call
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    Write-Log -Message 'Log started' -Severity INFO
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    If(-Not (Test-path $ArchiveFile)) {Write-Log -Message "$ArchiveFile was not created" -Severity FATAL}
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​
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.NOTES
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	  Source: https://berndplumhoff.gitbook.io/sulprobil/powershell
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    Version Date        Who                   What
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    1.0     16-Feb-2020 Bernd Plumhoff        Initial Version
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    1.1     16-Jul-2020 Bernd Plumhoff        EVER instead of ALWAYS, and optional Write-Host
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#>
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​
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#Set-ExecutionPolicy -ExecutionPolicy Bypass -Scope CurrentUser -Force
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#Clear
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Set-StrictMode -Version Latest
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​
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function Write-Log {
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    [CmdletBinding()]
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    param(
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        [Parameter()]
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        [ValidateNotNullOrEmpty()]
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        [string]$Message,
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        [Parameter()]
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        [ValidateNotNullOrEmpty()]
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        [ValidateSet('INFO','WARN','FATAL','EVER')]
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        [string]$Severity = 'INFO'
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    )
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    switch ($Severity)
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    {
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        'INFO'	{ If ([int]$global:LogLevel -gt 1) {Exit} }
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        'WARN'	{ If ([int]$global:LogLevel -gt 2) {Exit} }
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        'FATAL'	{ If ([int]$global:LogLevel -gt 3) {Exit} }
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        'EVER'	{ <# Will always be logged! #> }
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    }
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    if (-Not (Test-Path -IsValid $global:LogFilePath)) { $global:LogFilePath = "$PSScriptRoot\Logs\LogFile.txt" }
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    [string]$Output = $Severity + ": " + [System.Security.Principal.WindowsIdentity]::GetCurrent().Name +
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        " " + (Get-Date -UFormat "%Y-%m-%d %T") + " [" + $global:SubName + "] - " + $Message
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    Write-Output $Output | Out-File -append $global:LogFilePath
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	If (Test-Path variable:global:WriteToHost) {
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		If ($global:WriteToHost) { Write-Host $Output }
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	}
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}
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Eight Queens Puzzle
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