How does one change the end-of-line char(s)?

I spent about an hour searching the options for a way to get rid of \r from the end-of-line characters.  Oddly, it's not consistent.  Sometimes an edit to an existing line will result in the end-of-line characters being changed to \r\n from \n and sometimes it will not.  Is there a way to globally change the end-of-line char?

thanks,
-w