OptimizePowerShellStartup.ps1

###############################################################################################################
# Language     :  PowerShell 4.0
# Filename     :  OptimizePowerShellStartup.ps1
# Autor        :  BornToBeRoot (https://github.com/BornToBeRoot)
# Description  :  Optimize PowerShell startup by reduce JIT compile time with ngen.exe
# Repository   :  https://github.com/BornToBeRoot/PowerShell
###############################################################################################################

<#
    .SYNOPSIS
    Optimize PowerShell startup by reduce JIT compile time with "ngen.exe"

    .DESCRIPTION
    Optimize PowerShell startup by reduce JIT compile time with "ngen.exe".
	
	Script requires administrative permissions.

    .EXAMPLE
    OptimizePowerShellStartup.ps1
    
    .LINK
  	https://github.com/BornToBeRoot/PowerShell/blob/master/Documentation/Script/OptimizePowerShellStartup.README.md
#>

Begin{

}

Process{
	# Restart script/console as admin with parameters
	if(-not([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] "Administrator"))
	{
		$Arguments = "& '" + $MyInvocation.MyCommand.Definition + "'"
		Start-Process PowerShell.exe -Verb RunAs -ArgumentList $Arguments
		Break
	}

	Write-Host -Object "Start optimization..." -ForegroundColor Yellow

	# Set ngen path
	$ngen_path = Join-Path -Path $env:windir -ChildPath "Microsoft.NET"

	if($env:PROCESSOR_ARCHITECTURE -eq "AMD64")
	{
		$ngen_path = Join-Path -Path $ngen_path -ChildPath "Framework64\ngen.exe"
	}
	else
	{
		$ngen_path = Join-Path -Path $ngen_path -ChildPath "Framework\ngen.exe"
	}

	# Find latest ngen.exe
	$ngen_application_path = (Get-ChildItem -Path $ngen_path -Filter "ngen.exe" -Recurse | Where-Object {$_.Length -gt 0} | Select-Object -Last 1).Fullname

	Set-Alias -Name ngen -Value $ngen_application_path

	# Get assemblies and call ngen.exe
	[System.AppDomain]::CurrentDomain.GetAssemblies() | foreach { ngen install $_.Location /nologo /verbose}

	Write-Host -Object "Optimization finished!" -ForegroundColor Green

	Write-Host -Object "Press any key to continue..."
	[void]$host.UI.RawUI.ReadKey("NoEcho,IncludeKeyDown")
}

End{

}