VIM. Replace Windows line endings with Linux

When you see ^M instead of line breaks this might help you

:%s/<Ctrl-V><Ctrl-M>/\r/g

Where <Ctrl-V><Ctrl-M> means type Ctrl+V then Ctrl+M. 

Explanation

:%s

substitute, % = all lines

<Ctrl-V><Ctrl-M>

^M characters (the Ctrl-V is a Vim way of writing the Ctrl ^ character and Ctrl-M writes the M after the regular expression, resulting to ^M special character)

/\r/

with new line (\r)

g

And do it globally (not just the first occurrence on the line).

Source https://stackoverflow.com/questions/811193/how-to-convert-the-m-linebreak-to-normal-linebreak-in-a-file-opened-in-vim