Convert DOS line endings to Linux line endings in vim

If I open files I created in Windows, the lines all end with ^M.
How do I delete these characters all at once?

Answer

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.

Docs on the 'fileformat' setting are here, 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.