Delete-IISLogs.ps1

[CmdletBinding()]
param (
    [Parameter()]
    [int]
    $OlderThanXDays = 7
)

# Get IIS Site Log Files Path
Import-Module WebAdministration

## Get the IIS logs folder of all websites.
$iis_log_folders = @(
    Get-Website | ForEach-Object {
        New-Object psobject -Property $(
            [ordered]@{
                Site    = $_.Name;
                LogPath = $(($_.LogFile.Directory).ToString().Replace('%SystemDrive%', $env:SystemDrive)) + "\W3SVC$($_.id)\"
            }
        )
    }
)

## Delete the IIS log files older than $OlderThanXDays
$thresholdDate = (Get-Date).AddDays(-$OlderThanXDays)
$iis_log_folders.LogPath | ForEach-Object {
    Get-ChildItem -Path $_ -Filter *.log | `
        Where-Object { $_.LastWriteTime -lt $thresholdDate } | `
        Remove-Item -Confirm:$false -Force -Verbose
}