how to remove ^M in emacs [duplicate]

Question

How to remove ^M characters in Emacs?

It doesn't work using dos2unix filename or unix2dos filename.

This is what came out when I using command cat -A filename because normally I cannot see ^M characters.

Please explain it in plain words... and in detail...

cat -A ABC.sh
#!/bin/csh -f^M$
^M$
^M$
set input = `ls -1 *.py`^M$
echo $input^M$

Answer 1

[Searched for a duplicate, but didn't find one about replacing (instead of preventing etc.). If there is one then this one or that one should be closed.]

In Emacs, visit the file that has the ^M chars. Go to the beginning of the file (M-<), then:

M-x replace-string C-q C-m RET RET

That is, at the prompt for what to replace, use Control + q then Control + m, then Enter. At the prompt for what to replace it with, just hit Enter (replace it with nothing).

Answer 2

I've been using this

(defun delete-carrage-returns ()
  (interactive)
  (save-excursion
    (goto-char 0)
    (while (search-forward "\r" nil :noerror)
      (replace-match ""))))

I'm sure there is a better way, but this works well enough that I stopped looking.