Convert DOS line endings to Linux line endings in Vim

Change the line endings 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 line endings 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 *.cpp
do 
    vi +':w ++ff=unix' +':q' "$file"
done

dos2unix is a commandline utility that will do this, or :%s/^M//g will if you use Ctrl-v Ctrl-m to input the ^M, or you can :set ff=unix and Vim will do it for you.

There is documentation on the fileformat setting, and the Vim wiki has a comprehensive page on line ending conversions.

Alternately, if you move files back and forth a lot, you might not want to convert them, but rather to do :set ff=dos, so Vim will know it's a DOS file and use DOS conventions for line endings.