How to speed up Powershell Get-Childitem over UNC

Question

DIR or GCI is slow in Powershell, but fast in CMD. Is there any way to speed this up?

In CMD.exe, after a sub-second delay, this responds a

Answer 1

Here's an interactive reader that parses cmd /c dir (which can handle unc paths), and will collect the 3 most important properties for most people: full path, size, timestamp

usage would be something like $files_with_details = $faster_get_files.GetFileList($unc_compatible_folder)

and there's a helper function to check combined size $faster_get_files.GetSize($files_with_details)

$faster_get_files = New-Module -AsCustomObject -ScriptBlock {
    #$DebugPreference = 'Continue' #verbose, this will take figuratively forever
    #$DebugPreference = 'SilentlyContinue'
    $directory_filter = "Directory of (.+)"
    $file_filter = "(\d+/\d+/\d+)\s+(\d+:\d+ \w{2})\s+([\d,]+)\s+(.+)" # [1] is day, [2] is time (AM/PM), [3] is size,  [4] is filename
    $extension_filter = "(.+)[\.](\w{3,4})" # [1] is leaf, [2] is extension
    $directory = ""
    function GetFileList ($directory = $this.directory) {
        if ([System.IO.Directory]::Exists($directory)) {
            # Gather raw file list
            write-Information "Gathering files..."
            $files_raw = cmd /c dir $directory \*.* /s/a-d

            # Parse file list
            Write-Information "Parsing file list..."
            $files_with_details = foreach ($line in $files_raw) {
                Write-Debug "starting line {$($line)}"
                Switch -regex ($line) {
                    $this.directory_filter{
                        $directory = $matches[1]
                        break
                    }
                    $this.file_filter {
                        Write-Debug "parsing matches {$($matches.value -join ";")}"
                        $date     = $matches[1]
                        $time     = $matches[2] # am/pm style
                        $size     = $matches[3]
                        $filename = $matches[4]

                        # we do a second match here so as to not append a fake period to files without an extension, otherwise we could do a single match up above
                        Write-Debug "parsing extension from {$($filename)}"
                        if ($filename -match $this.extension_filter) {
                            $file_leaf = $matches[1]
                            $file_extension = $matches[2]
                        } else {
                            $file_leaf = $filename
                            $file_extension = ""
                        }
                        [pscustomobject][ordered]@{
                            "fullname"  = [string]"$($directory)\$($filename)"
                            "filename"  = [string]$filename
                            "folder"    = [string]$directory
                            "file_leaf" = [string]$file_leaf
                            "extension" = [string]$file_extension
                            "date"      = get-date "$($date) $($time)"
                            "size"      = [int]$size
                        }
                        break
                    } 
                } # finish directory/file test
            } # finish all files
            return $files_with_details
        } #finish directory exists test
        else #directory doesn't exist {throw("Directory not found")}
    }
    function GetSize($files_with_details) {
        $combined_size = ($files_with_details|measure -Property size -sum).sum
        $pretty_size_gb = "$([math]::Round($combined_size / 1GB, 4)) GB"
        return $pretty_size_gb
    }
    Export-ModuleMember -Function * -Variable *
}