readme.md

Two versions of Get-FolderSize, to get the size of a folder and its content.

One version is a pure Powershell one. The other uses Robocopy to do its job. The Robocopy version is usually quicker. The bigger the folder, the most impressive the difference (Sometimes though, the first access is slower, and I don't understand why).

Of note: Robocopy has been written as optimised for speed, whereas Powershell builds a .NET object for every file, hence the big difference in speed. Another plus of the Robocopy version is that it never breaks on long filepaths.

Get-FolderSize-test.ps1

function Get-FolderSizeRC($Path) {
    if ( robocopy $Path c:\dummy /e /r:0 /w:0 /b /BYTES /nfl /ndl /np /njh /l | ? { $_ -match 'Bytes :\s*(?<size>\S+)' } ) { return [int64]$Matches.size }
}

function Get-FolderSizePS($Path) {
    return ( ls -Recurse -Path $Path -Force | measure -Property length -Sum ) | select -ExpandProperty Sum
}

function test($Path) {
    Write-Host -Object "Testing $Path" -ForegroundColor Cyan
    "Read folder size (RC): $([math]::Round((Measure-Command { $size = Get-FolderSizeRC -Path $Path } | select -ExpandProperty TotalSeconds),1))s / $size ($([math]::Round(($size/1Mb)))Mb)"
    "Read folder size (PS): $([math]::Round((Measure-Command { $size = Get-FolderSizePS -Path $Path } | select -ExpandProperty TotalSeconds),1))s / $size ($([math]::Round(($size/1Mb)))Mb)"
}