pdf.ps1

$ghostscript = "C:\Program Files\gs\gs9.22\bin\gswin64c.exe"
$sumatrapdf = "C:\Program Files\SumatraPDF\SumatraPDF.exe"
$filename = $args[0]
if($filename.EndsWith("_gs.pdf")) {
	Start-Process $sumatrapdf -ArgumentList $filename
	exit
}
$nfn = $filename -replace "\.pdf$","_gs.pdf"
if(Test-Path $nfn -PathType leaf) {
	$orig_mt = (Get-Item $filename).LastWriteTime
	$new_mt = (Get-Item $nfn).LastWriteTime
	if($new_mt -ge $orig_mt) {
		Start-Process $sumatrapdf -ArgumentList $nfn
		exit
	}
}
& $ghostscript -q -sDEVICE=pdfwrite -o $nfn $filename
Start-Process $sumatrapdf -ArgumentList $nfn