vi/vim FAQ: How can I remove control-m (^M) characters in a text file using vi or vim?
If you've ever opened a text file with vi (or vim) and saw a message on the bottom of the screen that says "dos" or "dos format", there's a reason for this. The file was probably created on a DOS or Windows computer, and it contains extra binary characters that are not normally found in a file created on a Unix or Linux system.