Displays and removes Azure Network Interfaces that are not associated with a VM

Get-AzureOrphanedInterfaces.ps1

<#
.SYNOPSIS
	Deletes Azure Network Interfaces not associated with a VM
.DESCRIPTION
    Iterates through the network interfaces in an Azure subscription
    And deletes the interfaces not associated with a VM
    Will log to a file if LogFile parameter is passed
.PARAMETER Force
    Do not ask permission for each interface
    This will delete all interfaces that are not associated with a VM
.PARAMETER LogFile
    Path to a log file.  Will use basic text logging
.INPUTS
    [switch]Force
    [string]LogFile
#>
Param
(
	[Parameter(ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$true,Position=1)]
	[switch]$Force = $false,
    [Parameter(ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$true,Position=2)]    
	[string]$LogFile = $null
)
function CheckLogPath() {
#Check if path to log file exists
    if (![string]::IsNullOrEmpty($LogFile)) {
        try {
            [System.IO.Path]::GetDirectoryName($LogFile)
        } catch {
            $TryNewFile = Read-Host "Log directory does not exist, continue without a log file? (y/n)"
            if ($TryNewFile.ToLower() -eq "y") {
                $LogFile = $null
            } else {
                $LogFile = Read-Host "Enter a new log file: "                
                CheckLogPath
            }
        }
    }
}
CheckLogPath
function Write-Log {
    Param (
        [Parameter(ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$true,Position=1,Mandatory=$true)]
        [string]$LogLine
    )
    if (![string]::IsNullOrEmpty($LogFile)) { 
        $d = Get-Date
        $Dt = $d.ToUniversalTime()
        $Log = "$Dt - $LogLine"
        $Log | Add-Content $LogFile
    }
}
#Log if -Force flag is set
Write-Log -LogLine "Force Flag is set, will not prompt user for input"
#Log into your azure account
if ([string]::IsNullOrEmpty($(Get-AzureRmContext).Account)) {
    Write-Log -LogLine "Showing Azure Login Prompt"
    $null = Login-AzureRmAccount
} else {
    Write-Log -LogLine "User has already authenticated to Azure"
}
Write-Host "========Select a Subscription========"
$Subscriptions = Get-AzureRmSubscription
$i = 0
foreach ($Sub in $Subscriptions) {
    Write-Host "$i -" $Sub.Name
    $i++
}
do {
    $SelectedSub = Read-Host "Select a Subscription"
} while ($SelectedSub -ge $i -or $SelectedSub -lt 0)
$Subscription = $Subscriptions[$SelectedSub]
Write-Host "Changing to subscription" $Subscription.Name -ForegroundColor Green
try {
    $null = Select-AzureRmSubscription -SubscriptionId $Subscription.Id -ErrorAction Continue
    $SubscriptionName = $Subscription.Name
    Write-Log -LogLine "User selected subscription $SubscriptionName"
} catch {
    Write-Host "Error selecting Subscription $SubscriptionName.  Please ensure that you have access to this subscription and try again" -ForegroundColor Red
    Write-Log -LogLine "Error Accessing subscription $SubscriptionName"
    Write-Log -LogLine $_.Exception.Message
}
$OrphanedInterfaces = Get-AzureRmNetworkInterface | Where-Object { $_.VirtualMachine -eq $null }
if ($OrphanedInterfaces.length -le 0) {
    Write-Host "There are no orphaned interfaces in this subscription"
    Write-Log -LogLine "There are no orphaned interfaces in this subscription"
    exit
}
do {
    Write-Host "========Delete Interface========"
    $InterfacesToDelete = @{}
    $InterfacesToKeep = @{}
    foreach ($Int in $OrphanedInterfaces) {
        if ($Force) {
            $InterfacesToDelete.add($Int.Name, $Int.ResourceGroupName)  
        } else {
            $Delete = Read-Host $Int.Name " (y/n)"
            if ($Delete.ToLower() -eq "y") {
                $InterfacesToDelete.add($Int.Name, $Int.ResourceGroupName)        
            } else {
                $InterfacesToKeep.add($Int.Name, $Int.ResourceGroupName)        
            }
        }
    }
    foreach ($DelInt in $InterfacesToDelete.Keys) {
        Write-Host "Deleting" $DelInt -ForegroundColor Red
    }
    foreach ($SaveInt in $InterfacesToKeep.Keys) {
        Write-Host "Keeping" $SaveInt -ForegroundColor Green
    }
    $ConfirmDelete = Read-Host "Confirm delete (y/n)"
} while ($ConfirmDelete.ToLower() -ne "y" -and $ConfirmDelete.ToLower() -ne "n")
if ($ConfirmDelete.ToLower() -eq "y") {
    Write-Host "========DELETING INTERFACES========";
    foreach ($Del in $InterfacesToDelete.Keys) {
        try {
            $RG = $InterfacesToDelete[$Del]
            $null = Remove-AzureRmNetworkInterface -Name "$Del" -ResourceGroupName "$RG" -Force -ErrorAction Continue
            Write-Host "Deleted " $InterfacesToDelete[$Del]"/"$Del
            Write-Log -LogLine "Deleted" $InterfacesToDelete[$Del]"/"$Del
        } catch {
            Write-Host "Failed to delete $Del" -ForegroundColor Red
            Write-Log -LogLine "Failed to delete $Del"
            Write-Log -LogLine $_.Exception.Message
        }
    }
} else {
    Write-Host "User cancelled script.  Nothing has been deleted"
    Write-Log -LogLine "User cancelled script.  Nothing has been deleted"
}