anchor.diff:  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 
  
positive.code:     let fi = fileSystemInfo fileName
      
      match fi with
      | File f ->  
          let targetName = target @@ fi.Name
          DeleteFile targetName
          logVerbosefn "Move %s to %s" fileName targetName        
          f.MoveTo(targetName) |> ignore    
      | Directory _ -> logVerbosefn "Ignoring %s, because it is no file" fileName
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
  