Change the lineendings in the view:
:e ++ff=dos
:e ++ff=mac
:e ++ff=unix
This can also be used as saving operation (:w alone will not save using the lineendings you see on screen):
:w ++ff=dos
:w ++ff=mac
:w ++ff=unix
And you can use it from the command-line:
for file in $(ls *cpp)
do
vi +':w ++ff=unix' +':q' ${file}
done
http://stackoverflow.com/questions/82726/convert-dos-line-endings-to-linux-line-endings-in-vim