#requires -Version 2
 
$script:last_memory_usage_byte = 0
 
function Get-MemoryUsage
{
$memusagebyte = [System.GC]::GetTotalMemory('forcefullcollection')
$memusageMB = $memusagebyte / 1MB
$diffbytes = $memusagebyte - $script:last_memory_usage_byte
$difftext = ''
$sign = ''
if ( $script:last_memory_usage_byte -ne 0 )
{
if ( $diffbytes -ge 0 )
{
$sign = '+'
}
$difftext = ", $sign$diffbytes"
}
Write-Host -Object ('Memory usage: {0:n1} MB ({1:n0} Bytes{2})' -f $memusageMB,$memusagebyte, $difftext)
 
# save last value in script global variable
$script:last_memory_usage_byte = $memusagebyte
}

PS> Get-MemoryUsage
Memory usage: 6.7 MB (6,990,328 Bytes)
PS> $array = 1..100000
PS> Get-MemoryUsage
Memory usage: 10.2 MB (10,700,064 Bytes, +3709736)
PS> Remove-Variable -Name array
PS> Get-MemoryUsage
Memory usage: 7.4 MB (7,792,424 Bytes, -2907640)