Sometimes it's very unhelpful when vim automatically adds a linebreak at the end of file. Finally, I've became so irritated to switch to joe each time to correct the file, that I've found a solution.
It's very simple. It's enough to say:
:set noeol bin
After this the :w command writes the file without the last linebreak. But generally do not do this because a linebreak should normally always be at the end of a text file.