@echo off
:: Software and documentation is (c) 2013 GKX Associates Inc. and 
:: licensed under [GPL 2.0](https://www.gnu.org/licenses/gpl-2.0.html).
setlocal
if not "%2"=="" goto:run
echo Usage: copydir fromdir todir
echo All files/directories in fromdir that do not also exist in todir are 
echo recursively copied.
echo e.g. 
echo      cd "%userprofile%\Documents\R\win-library"
echo      movedir 2.14 2.15
echo Now start up R 2.15.x and issue update.packages()
goto:eof
:run
for /D  %%a in ("%~1\*") do if not exist %2\%%~na move "%%a" "%~2\%%~nxa"
endlocal
