You have to use double slashes in this case:
taskkill //PID 13588
This is documented here: http://www.mingw.org/wiki/Posix_path_conversion
Look at the examples on this page, especially the //foobar example.
You have to use double slashes in this case:
taskkill //PID 13588
This is documented here: http://www.mingw.org/wiki/Posix_path_conversion
Look at the examples on this page, especially the //foobar example.