To remove the ^M characters at the end of all lines in vi, use:
The ^v is a CONTROL-V character and ^m is a CONTROL-M. When you type this, it will look like this:
In UNIX, you can escape a control character by preceeding it with a CONTROL-V. The :%s is a basic search and replace command in vi. It tells vi to replace the regular expression between the first and second slashes (^M) with the text between the second and third slashes (nothing in this case). The g at the end directs vi to search and replace globally (all occurrences).
Another way to get rid of those ^M's:
cat old.file | col -b > new.file
tr -d '\r' <old.file > new.file
You can also use the octal representatiion of ^M. The following gets rid of control-M as well as control-Z (DOS eof marker):
tr -d '\015\032' < file