rename.ps1

#https://stackoverflow.com/questions/1523043/how-to-loop-through-files-and-rename-using-powershell
#https://stackoverflow.com/questions/2038181/how-to-output-something-in-powershell
#https://stackoverflow.com/questions/15113413/how-do-i-concatenate-strings-and-variables-in-powershell
#https://habr.com/ru/post/242445/
#https://stackoverflow.com/questions/39761059/display-file-names
#https://windowsnotes.ru/powershell-2/powershell-i-regulyarnye-vyrazheniya-chast-1/

cls;
$files = Get-ChildItem $(pwd)  -Filter *.mp4| select BaseName;
foreach($f in $files)
{
    if(
        [string]$f -match "BaseName\=(?'gname'(?:variant1|variant2|variant3).?(?'number'[\d]+)(?:.?\-.?)(?'name'.*))\}"
    ){
        $name   = [string]$Matches['name'];
        $number = [int]$Matches['number'];
        $gname  = [string]$Matches['gname'];

	    if( ($number -ge 1) -and ($number -le 9) ){
         $nm="000"+$number;
        }elseif( ($number -ge 10) -and ($number -le 99) ){
         $nm="00"+$number;
        }elseif($number -ge 100){
         $nm="0"+$number;
        }
 
        Write-Output $gname".mp4";
        Write-Output $nm"___"$name;
        #
        #
	      #Rename-Item $gname".mp4" -NewName $nm"___"$name".mp4";
    }
}