PowerShell Delete more quickly - powershell

Question

I have a PowerShell script that recursively deletes all files and folders, but excludes certain folders as they should not be deleted.
It works 100%, but my problem is performance. I need this to run a lot faster.
Any ideas on how to make this faster?
Write-Host "Purging $InstallationDirectorySite - Deleting files..."
$FolderExlusions = (
"App_Data",
"Logs",
"TEMP",
"ExamineIndexes",
"DistCache",
"GitPathProviderRepository"
)
[regex] $files_regex = "Logs|ExamineIndexes|DistCache*|GitPathProviderRepository*"
if(Test-Path $InstallationDirectorySite) {
Get-ChildItem -Path $InstallationDirectorySite -Recurse -Exclude $FolderExlusions |
Where-Object {$_.FullName -notmatch $files_regex} |
Remove-Item -Recurse
}
else {
Write-Output "$InstallationDirectorySite doesn't exist"
}

Answer 1

You are in fact filtering the excluded folders twice.
The first time using the -Exclude parameter and the second time using a Regex -match.
However, the Exclude parameter takes a string array, not a single string with keywords separated by a comma and a newline as you get from the 'here-string'.
See Get-ChildItem
Also, the regex you use is wrong, because the asteriks * in regex is a quantifier, not a wildcard character.
I suggest you filter once using either the -Exclude parameter like this (here the asteriks is a Wildcard):
$FolderExlusions = "App_Data","Logs","TEMP","ExamineIndexes","DistCache*","GitPathProviderRepository*"
Get-ChildItem -Path $InstallationDirectorySite -Recurse -Exclude $FolderExlusions | Remove-Item -Recurse -WhatIf
Or use only the regex method in a Where-Object clause like this:
$FolderExlusions = "^(App_Data|Logs|TEMP|ExamineIndexes|DistCache.*|GitPathProviderRepository.*)"
Get-ChildItem -Path $InstallationDirectorySite -Recurse | Where-Object { $_.Name -notmatch $FolderExlusions } | Remove-Item -Recurse -WhatIf
Remove the -WhatIf if you are satisfied with the results.
Hope that helps