anchor.diff:          let targetName = target @@ fi.Name
           DeleteFile targetName
           logVerbosefn "Move %s to %s" fileName targetName
  -        ensureDirectory target
           f.MoveTo(targetName) |> ignore
       | Directory _ -> logVerbosefn "Ignoring %s, because it is no file" fileName
positive.code: let AppendTextFiles newFileName files =    
      let fi = fileInfo newFileName
      if fi.Exists then failwithf "File %s already exists." (fi.FullName)
      ensureDirExists fi.Directory
      use writer = new StreamWriter(fi.FullName, false, Encoding.Default)
    
      files 
  
negative.code:         let fi = file |> replaceFirst source "" |> trimSeparator
          let newFile = target @@ fi
          logVerbosefn "%s => %s" file newFile
          DirectoryName newFile |> ensureDirectory
          File.Copy(file, newFile, true))
      |> ignore
    
  