anchor.diff:  function Do-Copy($src,$dst){
       Write-Verbose "$ copy '$src' '$dst'"
       Copy-Item $src $dst
  +}
  +
  +function Do-Rename($old,$new){
  +    Write-Verbose "$ ren $old $new"
  +    Rename-Item -path $old -newname $new
   }
   
   function Do-Remove($file){
  
positive.code:     }
  }
  
  Add-Type -Assembly System.Windows.Forms
  function Ask-Copy($src,$dst){
      $fname = (Join-Path $dst (Split-Path $src -Leaf))
      if( Test-Path $fname ){
          if( "Yes" -ne [System.Windows.Forms.MessageBox]::Show(
              'Override "{0}" by default ?' -f $fname,
              "NYAGOS Install", "YesNo","Question","button2") ){
              return
          }
      }
      Do-Copy $src $dst
  }
  
  function ForEach-GoDir{
  
negative.code:             $now = (Get-Date -Format "yyyyMMddHHmmss")
              try{
                  $old = (Join-Path $installDir "nyagos.exe")
                  Do-Rename $old ($old + "-" + $now)
                  Do-Copy nyagos.exe $installDir
              }catch{
                  Write-Host "Could not update installed nyagos.exe"
                  Write-Host "Some processes holds nyagos.exe now"
              }
          }
      }
      "get" {
  