Trying to implement if statement based on percentage

Question

Im building a script but I cannot get it to complete, because im struggling getting the if statement working.

$freespace = [math]::round((Get-WmiObject Win32_Volume -Filter "Label='User Disk'" | Foreach-Object {$_.FreeSpace})/ 1MB)
$volumespace = [math]::round((Get-WmiObject Win32_Volume -Filter "Label='User Disk'" | Foreach-Object {$_.Capacity})/ 1MB)
$usedspace=$volumespace-$freespace

Write-Host
"Used Space: $usedspace"
"Free Space: $freespace"
"Total Space Assigned: $volumespace"

if ($freespace -lt 5% $volumespace)

The if statement needs to calculate like this (pseudo code):

if $freespace is less than 5% of the $volumespace

then my send mail command get attached to it.

I don't know how to make this calculation, despite struggling for hours.

Answer 1

$freeSpace -lt $volumeSpace * .05 is the conditional you're looking for:

• -lt is PowerShells less-than operator (< in other languages)
• decimal fraction .5 (0.05) represents 5% and is of type [double], the same as your variables.

The following streamlined version of your code demonstrates use of a variable to store the percentage:

$freeSpace, $volumeSpace = Get-WmiObject Win32_Volume -Filter "Label='User Disk'" | 
  ForEach-Object { [math]::Round($_.FreeSpace / 1mb), [math]::Round($_.Capacity / 1mb) }

$usedSpace = $volumeSpace - $freeSpace

$thresholdPercentage = 5

# Send email if there's less than 5% free space.
# Note the need to divide the percentage number by 100.
# Alternatively, define $thresholdPercentage as 0.05 above.
if ($freeSpace -lt $volumeSpace * ($thresholdPercentage / 100)) {
   # Send email
}